阅读说明：本技术 聚合物组合物、成型体、光学构件和聚合物组合物的制造方法 (Polymer composition, molded body, optical member, and method for producing polymer composition ) 是由 冈崎亮辅 真锅诚 于 2020-01-30 设计创作，主要内容包括：本发明提供一种具有充分的耐热性和光学特性的聚合物组合物。一种聚合物组合物,所述聚合物组合物包含聚合物,所述聚合物含有具有环结构的单体单元,其中,该聚合物组合物为包含具有环结构的单体的聚合物的聚合物组合物A等,并且在以下的注射成型条件下由该聚合物组合物成型出120mm×100mm×厚度3.0mm的平板时,在冷却时间为5分钟的条件下得到的所述平板中的单体含量与在冷却时间为1分钟的条件下得到的所述平板中的单体含量之差为1000质量ppm以上且12000质量ppm以下,所述注射成型条件为：(1)使用非排气式注射成型机；(2)使用冷流道方式的模具；(3)料筒温度为260℃；和(4)注射成型机的注射体积相对于成型品的体积之比为4.5。(The present invention provides a polymer composition having sufficient heat resistance and optical characteristics. A polymer composition comprising a polymer containing a monomer unit having a ring structure, wherein the polymer composition is a polymer composition A or the like comprising a polymer of a monomer having a ring structure, and when a flat plate of 120mm x 100mm x 3.0mm in thickness is molded from the polymer composition under the following injection molding conditions, the difference between the monomer content in the flat plate obtained under a condition of a cooling time of 5 minutes and the monomer content in the flat plate obtained under a condition of a cooling time of 1 minute is 1000ppm by mass or more and 12000ppm by mass or less, the injection molding conditions being: (1) using a non-vented injection molding machine; (2) a cold runner type mold; (3) the temperature of the charging barrel is 260 ℃; and (4) the ratio of the injection volume of the injection molding machine to the volume of the molded article was 4.5.)

1. A polymer composition comprising a polymer containing a monomer unit having a ring structure, wherein,

the polymer composition is a polymer composition A comprising a polymer of a monomer having a ring structure, or a polymer composition which is a cyclization product of a polymer composition B comprising a precursor polymer which is a polymer of two or more monomers capable of forming a ring together, and

when a flat plate of 120mm x 100mm x 3.0mm in thickness is molded from the polymer composition under the following injection molding conditions, the difference between the monomer content in the flat plate obtained under a cooling time of 5 minutes and the monomer content in the flat plate obtained under a cooling time of 1 minute is 1000 mass ppm or more and 12000 mass ppm or less,

the injection molding conditions were:

(1) using a non-vented injection molding machine;

(2) a cold runner type mold;

(3) the temperature of the charging barrel is 260 ℃; and

(4) the ratio of the injection volume of the injection molding machine to the volume of the molded article was 4.5.

2. The polymer composition according to claim 1, wherein the monomer unit having a ring structure comprises one or more selected from the group consisting of a glutaric anhydride structural unit, a maleic anhydride structural unit, a maleimide structural unit, a glutarimide structural unit, and a lactone structural unit.

3. The polymer composition of claim 2, wherein the monomer unit having a ring structure comprises a glutaric anhydride structural unit.

4. The polymer composition according to any one of claims 1 to 3, further comprising a phosphorus-containing antioxidant, and the content of the phosphorus-containing antioxidant is 0.005 parts by mass or more and 0.2 parts by mass or less with respect to 100 parts by mass of the polymer.

5. The polymer composition according to any one of claims 1 to 4, wherein the polymer contains, as a monomer unit other than the monomer unit having a ring structure, one or more selected from the group consisting of a monomer unit derived from methacrylic acid, a monomer unit derived from a methacrylate ester, a monomer unit derived from acrylic acid, and a monomer unit derived from an acrylate ester.

6. The polymer composition according to any one of claims 1 to 5, wherein the polymer contains more than 0.15 mol% and 5 mol% or less of the monomer unit having a ring structure relative to all monomer units constituting the polymer.

7. A molded article comprising the polymer composition according to any one of claims 1 to 6.

8. An optical member, wherein the optical member comprises the molded body according to claim 7.

9. A method for producing the polymer composition containing a polymer containing a monomer unit having a ring structure according to any one of claims 1 to 6, the method comprising:

a step of extruding a polymer composition A or a polymer composition B using an extruder at a cylinder temperature of 240 ℃ or more and 270 ℃ or less to obtain a polymer composition, wherein the polymer composition A contains a polymer of a monomer having a ring structure, and the polymer composition B contains a precursor polymer, and the precursor polymer is a polymer of two or more monomers capable of forming a ring together.

10. The method according to claim 9, wherein a cyclized product of the polymer composition B comprising a precursor polymer which is a polymer of two or more monomers capable of forming a ring together is obtained by the extrusion.

Technical Field

The present invention relates to a polymer composition, a molded article composed of the polymer composition, an optical member including the molded article, and a method for producing the polymer composition.

Background

Polymers such as polymethyl methacrylate, polystyrene, and a methyl methacrylate-styrene copolymer are used in a wide range of fields such as vehicle members, electrical related members, and industrial members because of their excellent transparency, mechanical properties, molding processability, and the like.

Depending on the field of use, such polymers and molded articles are sometimes required to have more excellent properties in terms of optical properties such as transparency, molding processability, heat resistance, weather resistance, strength and the like. For example, in the field of vehicle members and the like, the above-mentioned polymers are used as a material for optical members such as optical lenses of lamps. Since it is assumed that a higher-luminance LED lamp will be used as a light source of a lamp in the future, a polymer is required to have sufficient heat resistance and optical properties. Therefore, various attempts have been made to improve the heat resistance and optical properties of polymers.

For example, patent document 1 discloses an acrylic resin having a content of an acid anhydride unit having a 6-membered ring structure of 0.01 to 10 parts by mass and a specific weight average molecular weight as an acrylic resin having improved heat resistance and high colorless transparency.

Patent document 2 discloses a copolymer containing 80 mol% or more of methyl (meth) acrylate units as a copolymer excellent in heat resistance, appearance, and the like.

Patent document 3 discloses a thermoplastic resin composition containing a copolymer and an antioxidant, and containing a repeating unit having a glutaric anhydride structure in an amount of 0.001 to 0.15 mol% as a thermoplastic resin composition having excellent heat resistance, appearance, weather resistance, and the like.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2009-256406

Patent document 2: international publication No. 2017/022393

Patent document 3: international publication No. 2019/013186

Disclosure of Invention

Problems to be solved by the invention

However, the acrylic resin proposed in patent document 1 and the copolymer proposed in patent document 2 are limited to a method in which the amount of monomer units in the resin or polymer is set within a specific range, and when the polymer obtained by this method is used as the optical member, heat resistance and optical characteristics are insufficient.

The thermoplastic resin composition proposed in patent document 3 is improved in coloring by blending an antioxidant, but the content of a repeating unit having a glutaric anhydride structure is small, and therefore the heat resistance is not necessarily sufficient.

Accordingly, an object of the present invention is to provide a polymer composition having sufficient heat resistance and optical characteristics, a molded article made of the polymer composition, an optical member including the molded article, and a method for producing the polymer composition.

Means for solving the problems

The present inventors have conducted intensive studies to solve the above problems, and as a result, have completed the present invention. That is, the present invention includes the following preferred embodiments.

[1] A polymer composition comprising a polymer containing a monomer unit having a ring structure, wherein,

the polymer composition is a polymer composition A comprising a polymer of a monomer having a ring structure, or a polymer composition which is a cyclization product of a polymer composition B comprising a precursor polymer which is a polymer of two or more monomers capable of forming a ring together, and

when a flat plate of 120mm x 100mm x 3.0mm in thickness is molded from the polymer composition under the following injection molding conditions, the difference between the monomer content in the flat plate obtained under a cooling time of 5 minutes and the monomer content in the flat plate obtained under a cooling time of 1 minute is 1000 mass ppm or more and 12000 mass ppm or less,

the injection molding conditions were:

(1) using a non-vented injection molding machine;

(2) a cold runner type mold;

(3) the temperature of the charging barrel is 260 ℃; and

(4) the ratio of the injection volume of the injection molding machine to the volume of the molded article was 4.5.

[2] The polymer composition according to [1], wherein the monomer unit having a ring structure contains at least one selected from the group consisting of a glutaric anhydride structural unit, a maleic anhydride structural unit, a maleimide structural unit, a glutarimide structural unit, and a lactone structural unit.

[3] The polymer composition according to [2], wherein the monomer unit having a ring structure comprises a glutaric anhydride structural unit.

[4] The polymer composition according to any one of the above [1] to [3], further comprising a phosphorus-containing antioxidant, and a content of the phosphorus-containing antioxidant is 0.005 parts by mass or more and 0.2 parts by mass or less with respect to 100 parts by mass of the polymer.

[5] The polymer composition according to any one of the above [1] to [4], wherein the polymer contains, as a monomer unit other than the monomer unit having a ring structure, one or more selected from the group consisting of a monomer unit derived from methacrylic acid, a monomer unit derived from methacrylic acid ester, a monomer unit derived from acrylic acid, and a monomer unit derived from acrylic acid ester.

[6] The polymer composition according to any one of the above [1] to [5], wherein the polymer contains the monomer unit having a ring structure in an amount of more than 0.15 mol% and 5 mol% or less based on all monomer units constituting the polymer.

[7] A molded article comprising the polymer composition according to any one of the above [1] to [6 ].

[8] An optical member, wherein the optical member comprises the molded body according to [7 ].

[9] A method for producing a polymer composition containing a polymer containing a monomer unit having a ring structure according to any one of [1] to [6], the method comprising:

a step of extruding a polymer composition A or a polymer composition B using an extruder at a cylinder temperature of 240 ℃ or more and 270 ℃ or less to obtain a polymer composition, wherein the polymer composition A contains a polymer of a monomer having a ring structure, and the polymer composition B contains a precursor polymer, and the precursor polymer is a polymer of two or more monomers capable of forming a ring together.

[10] The method according to [9], wherein the extrusion gives a cyclized product of the polymer composition B comprising a precursor polymer of two or more monomers which can form a ring together.

Effects of the invention

According to the present invention, a polymer composition having sufficient heat resistance and optical characteristics, a molded article made of the polymer composition, an optical member containing the molded article, and a method for producing the polymer composition can be provided.

Drawings

FIG. 1 is a view showing a non-vented injection molding machine for molding the polymer composition of the present invention.

FIG. 2 is a view showing a test molded piece produced by injection molding from the polymer composition of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described herein, and various modifications may be made without departing from the spirit of the present invention.

< Polymer composition >

The polymer composition of the present invention comprises a polymer containing a monomer unit having a ring structure. The polymer composition is a polymer composition A containing a polymer of a monomer having a ring structure, or a polymer composition which is a cyclization product of a polymer composition B containing a precursor polymer which is a polymer of two or more monomers capable of forming a ring together.

In the present specification, examples of the monomer unit having a ring structure include a monomer unit including a ring structure derived from a monomer having a ring structure and a monomer unit including a ring structure formed by condensation reaction or the like of two or more monomers capable of forming a ring together. One or both of the above-described monomer units may be contained in the polymer as a monomer unit having a ring structure.

In the present specification, "two or more monomers capable of forming a ring together" means any two or more monomers of: in a polymer obtained by polymerizing two or more kinds of monomers, 1 ring structure is formed in the polymer by a reaction (for example, a condensation reaction) of any one kind of monomer unit with any other kind of monomer unit, and the polymer becomes a monomer unit having a ring structure.

In the present specification, the term "(meth) acrylic acid" means "acrylic acid" or "methacrylic acid".

The polymer and other components contained in the polymer composition of the present invention will be described in detail below.

(A) Polymer and method of making same

(a) Monomer unit having ring structure

The monomer unit having a ring structure (hereinafter also referred to as a ring-structured monomer unit) is not particularly limited. Preferably, the cyclic monomer unit is a 6-membered cyclic monomer unit or a 5-membered cyclic monomer unit.

The cyclic monomer unit includes, for example, one or more selected from the group consisting of a glutaric anhydride structural unit, a maleic anhydride structural unit, a maleimide structural unit, a glutarimide structural unit, and a lactone structural unit. The cyclic monomer unit preferably comprises a glutaric anhydride structural unit. The cyclic monomer unit in each specific example will be described below.

Glutaric anhydride building block (a-1)

The glutaric anhydride structural unit is shown in the following formula (1).

[ in the formula (1), R¹、R²And R³Each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, preferably a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, still more preferably a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and

the alkyl group may be substituted with a hydroxyl group. ]

The glutaric anhydride structural unit (a-1) can be formed, for example, by using an acrylic ester and acrylic acid or a methacrylic ester and methacrylic acid as raw material monomers and subjecting a polymer obtained by polymerization of these monomers to a cyclization reaction. When the polymer contains the glutaric anhydride structural unit (a-1), the heat resistance of a molded article made of the polymer composition can be improved.

Maleic anhydride structural Unit (a-2)

The maleic anhydride structural unit is shown in the following formula (2).

[ in the formula (2), R⁴And R⁵Each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a carbon atomA substituted or unsubstituted alkyl group having 1 or more and 20 or less, preferably a substituted or unsubstituted alkyl group having 1 or more and 12 or less carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 or more and 8 or less carbon atoms, still more preferably a substituted or unsubstituted alkyl group having 1 or more and 6 or less carbon atoms, and

the alkyl or aryl group may be substituted with a hydroxyl group. ]

The maleic anhydride structural unit (a-2) is contained in a polymer obtained by copolymerization using a substituted or unsubstituted maleic anhydride as a raw material monomer. Examples of the substituted or unsubstituted maleic anhydride include: maleic anhydride, citraconic anhydride, dimethylmaleic anhydride, dichloromaleic anhydride, bromomaleic anhydride, dibromomaleic anhydride, phenylmaleic anhydride, diphenylmaleic anhydride, and the like. Among these substituted or unsubstituted maleic anhydrides, maleic anhydride is preferably used from the viewpoint of facilitating copolymerization for obtaining a polymer.

Maleimide structural Unit (a-3)

The maleimide structural unit is shown in the following formula (3).

[ in the formula (3), R⁶And R⁷Each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, preferably a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, still more preferably a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms,

R⁸represents a hydrogen atom or one selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 12 carbon atoms, a substituted or substituted aryl group having 6 to 18 carbon atoms and a substituted or unsubstituted aryloxy group having 6 to 18 carbon atoms, and

the alkyl, alkoxy, aryl or aryloxy group may be substituted with a hydroxyl group. ]

The above formula (3) is preferably as follows.

[ in the formula (3), R⁶And R⁷Each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms,

R⁸represents a hydrogen atom or one selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms and a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms, and

the alkyl, alkoxy, aryl or aryloxy group may be substituted with a hydroxyl group. ]

The maleimide structural unit (a-3) may be contained in the polymer by using a specific monomer, for example. The raw material monomer is not particularly limited. Examples thereof include: n-aryl substituted maleimides such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide, N-ethylphenylmaleimide, N-butylphenyl maleimide, N-dimethylphenylmaleimide, N-methylphenylmaleimide, N-methoxyphenylmaleimide, N- (o-chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide and N- (p-chlorophenyl) maleimide.

Glutarimide structural Unit (a-4)

A glutarimide structural unit is shown in the following formula (4).

[ in the formula (4), R⁹、R¹⁰And R¹¹Each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, preferably the number of carbon atomsA substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, still more preferably a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms,

R¹²represents a hydrogen atom or one selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms and a substituted or unsubstituted aryloxy group having 6 to 18 carbon atoms, and

the alkyl, alkoxy, aryl or aryloxy group may be substituted with a hydroxyl group. ]

The above formula (4) is preferably as follows.

[ in the formula (4), R⁹、R¹⁰And R¹¹Each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms,

R¹²represents a hydrogen atom or one selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms and a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms, and

the alkyl, alkoxy, aryl or aryloxy group may be substituted with a hydroxyl group. ]

The glutarimide structural unit (a-4) can be contained in the polymer by, for example, a method of copolymerizing using methacrylate ester and/or methacrylic acid as raw material monomers and reacting ammonia, amine, or urea at high temperature. Alternatively, a known method such as a method of reacting polymethacrylic anhydride with ammonia or an amine may be used.

Lactone structural Unit (a-5)

The lactone structural unit is shown in the following formula (5).

[ in the formula (5), R¹³、R¹⁴And R¹⁵Each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, preferably a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, still more preferably a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms,

R¹⁶represents a hydrogen atom or one selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms and a substituted or unsubstituted aryloxy group having 6 to 18 carbon atoms, and

the alkyl, alkoxy, aryl or aryloxy group may be substituted with a hydroxyl group. ]

The above formula (5) is preferably as follows.

[ in the formula (5), R¹³、R¹⁴And R¹⁵Each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms,

R¹⁶represents a hydrogen atom or one selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms and a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms, and

the alkyl, alkoxy, aryl or aryloxy group may be substituted with a hydroxyl group. ]

The method for introducing the lactone structural unit (a-5) into the polymer is not particularly limited. The lactone structure can be formed, for example, by copolymerizing acrylic acid or acrylic acid ester having a hydroxyl group as a substituent with methacrylic acid ester such as methyl methacrylate as a raw material monomer, further introducing a hydroxyl group and an ester group or a carboxyl group into the molecular chain, and subjecting these hydroxyl group and ester group or carboxyl group to dealcoholization or dehydration condensation.

As the acrylic acid or acrylic ester having a hydroxyl group used for polymerization, for example, there can be mentioned: 2- (hydroxymethyl) acrylic acid, 2- (hydroxyethyl) acrylic acid, alkyl 2- (hydroxymethyl) acrylate, alkyl 2- (hydroxyethyl) acrylate, preferably 2- (hydroxymethyl) acrylic acid or alkyl 2- (hydroxymethyl) acrylate having a hydroxyallyl moiety. Examples of the alkyl 2- (hydroxymethyl) acrylate include: methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, isopropyl 2- (hydroxymethyl) acrylate, n-butyl 2- (hydroxymethyl) acrylate, t-butyl 2- (hydroxymethyl) acrylate, and the like. Among them, methyl 2- (hydroxymethyl) acrylate or ethyl 2- (hydroxymethyl) acrylate is particularly preferable.

The cyclic structure monomer unit is contained in the polymer in a proportion of preferably more than 0.15 mol% and not more than 5 mol%, more preferably in a proportion of 0.2 mol% or more and not more than 4.5 mol%, further preferably in a proportion of 0.26 mol% or more and not more than 4 mol%, further preferably in a proportion of 0.3 mol% or more and not more than 3 mol%, and further preferably in a proportion of 0.6 mol% or more and not more than 1 mol% with respect to the total monomer units constituting the polymer contained in the polymer composition of the present invention.

The proportion (% by mole) of the cyclic monomer unit in the polymer contained in the polymer composition of the present invention is determined by using¹³The C-NMR method calculates the integral value of peaks in the peak range corresponding to each cyclic monomer unit. Alternatively, depending on the ring structure contained, it is also possible to use¹³C-NMR method and further use¹H-NMR method and/or IR method.

(b) Monomer units other than those having a ring structure

The polymer contained in the polymer composition of the present invention may contain a monomer unit other than a monomer unit having a cyclic structure (hereinafter, also referred to as a non-cyclic monomer unit).

The non-cyclic monomer units are derived from the starting monomers of the polymer contained in the polymer composition. The monomer is not particularly limited as long as it is a polymerizable vinyl monomer. The non-cyclic monomer unit may include a monomer unit in which monomers capable of forming a ring together do not form the ring structure but exist in the polymer as a non-cyclic monomer unit.

For example, the non-cyclic structure monomer unit may include one or more selected from the group consisting of a monomer unit derived from methacrylic acid (formula (6) below), a monomer unit derived from a methacrylate ester (formula (7) below), a monomer unit derived from acrylic acid (formula (8) below), a monomer unit derived from an acrylate ester (formula (9) below), and a monomer unit derived from an aromatic vinyl compound (formula (10) below). The non-cyclic structure monomer unit preferably contains one or more selected from the group consisting of a monomer unit derived from methacrylic acid, a monomer unit derived from a methacrylate ester, a monomer unit derived from acrylic acid, and a monomer unit derived from an acrylate ester.

[ in formula (7), R¹⁸Represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, preferably a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, still more preferably a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and

the alkyl group may be substituted with a hydroxyl group. ]

[ in formula (9), R²⁰Represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, preferably a carbon atomA substituted or unsubstituted alkyl group having 1 or more and 12 or less, a substituted or unsubstituted alkyl group having 1 or more and 8 or less carbon atoms is more preferable, a substituted or unsubstituted alkyl group having 1 or more and 6 or less carbon atoms is further preferable, and

the alkyl group may be substituted with a hydroxyl group. ]

[ in formula (10), R²¹Represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, preferably a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, still more preferably a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms,

n represents an integer of 0 to 5 inclusive,

R²²represents a hydrogen atom or any one selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms and a substituted or unsubstituted aryloxy group having 6 to 18 carbon atoms,

R²²may be the same group throughout or different groups,

R²²can form a ring structure with each other, an

The alkyl, alkoxy, aryl or aryloxy group may be substituted with a hydroxyl group. ]

When the polymer contained in the polymer composition of the present invention contains the above-mentioned non-cyclic monomer unit, the raw material monomer may contain two or more selected from the group consisting of methacrylic acid, methacrylic acid ester (formula (11) below), acrylic acid ester (formula (12) below), and aromatic vinyl compound (formula (13) below). The raw material monomer may be a single kind or plural kinds. The raw material monomer preferably contains two or more selected from the group consisting of methacrylic acid, methacrylic acid ester, acrylic acid, and acrylic acid ester, and more preferably contains methacrylic acid and methacrylic acid ester.

[ in formula (11), R¹⁷Represents a methyl group, and is represented by,

R¹⁸represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, preferably a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, still more preferably a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and

the alkyl group may be substituted with a hydroxyl group. ]

Examples of the methacrylic acid ester represented by the above formula (11) include: methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, 2-ethylhexyl methacrylate, (t-butylcyclohexyl) methacrylate, benzyl methacrylate, 2,2, 2-trifluoroethyl methacrylate, and the like, but are not limited thereto. The methacrylic acid ester may be used alone or in combination of two or more.

[ in formula (12), R¹⁹Represents a hydrogen atom, and is represented by,

R²⁰represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, preferably a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, still more preferably a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and

the alkyl group may be substituted with a hydroxyl group. ]

Examples of the acrylate represented by the above formula (12) include: methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, and the like, but are not limited thereto. The acrylic acid ester may be used alone or in combination of two or more.

[ in formula (13), R²¹Represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, preferably a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, still more preferably a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms,

n represents an integer of 0 to 5 inclusive,

R²²represents a hydrogen atom or any one selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms and a substituted or unsubstituted aryloxy group having 6 to 18 carbon atoms,

R²²may be the same group throughout or different groups,

R²²can form a ring structure with each other, an

The alkyl, alkoxy, aryl or aryloxy group may be substituted with a hydroxyl group. ]

Examples of the aromatic vinyl compound represented by the above formula (13) include: styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2, 4-dimethylstyrene, 2, 5-dimethylstyrene, 3, 4-dimethylstyrene, 3, 5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, p-tert-butylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1-diphenylethylene, isopropenylbenzene (α -methylstyrene), isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene, etc., but are not limited thereto. The aromatic vinyl compound may be used alone or in combination of two or more.

Although not particularly limited, the polymer contained in the polymer composition of the present invention obtained from the above-mentioned monomers contains, for example, a structural unit having the following cyclic monomer unit in a part of the polymer. In the formula, n represents an integer.

For example, the following structural unit having a glutaric anhydride structural unit (a-1) (the following formula (14)) is formed by using methyl methacrylate, methacrylic acid, and styrene as raw material monomers.

For example, the following structural unit having a glutaric anhydride structural unit (a-1) (the following formula (15)) is formed by using methyl methacrylate and methacrylic acid as raw material monomers.

For example, the following structural unit having a maleic anhydride structural unit (a-2) (the following formula (16)) is formed by using methyl methacrylate, maleic anhydride, styrene, and α -methylstyrene as raw material monomers.

For example, the following structural unit having a maleimide structural unit (a-3) (the following formula (17)) is formed by using methyl methacrylate, N-cyclohexylmaleimide and styrene as raw material monomers.

For example, the following structural unit having a lactone structural unit (a-5) (the following formula (18)) is formed by using methyl methacrylate, methacrylic acid, and methyl 2- (hydroxymethyl) acrylate as raw material monomers.

The proportion of the non-cyclic monomer unit relative to the total monomer units constituting the polymer is a value (mol%) obtained by subtracting mol% of the cyclic monomer unit contained in the polymer from 100 mol%.

As an example, a case where (meth) acrylic acid and (meth) acrylic acid ester are used as a part or all of raw material monomers will be described. In such cases, the precursor polymer may comprise monomeric units derived from (meth) acrylic acid and monomeric units derived from a (meth) acrylate ester. Further, the polymer after undergoing a cyclized condensation reaction by extrusion or the like may contain a monomer unit derived from (meth) acrylic acid, a monomer unit derived from (meth) acrylic acid ester, and a glutaric anhydride structural unit obtained by cyclized condensation of (meth) acrylic acid and (meth) acrylic acid ester.

In such a polymer, the monomer unit derived from a (meth) acrylic acid ester may be contained in an amount of preferably 80 mol% or more and 98.99 mol% or less, more preferably 90 mol% or more and 95 mol% or less, particularly preferably 92.8 mol% or more and 94.2 mol% or less, the monomer unit derived from a (meth) acrylic acid ester may be contained in an amount of preferably 0.5 mol% or more and 12.8 mol% or less, more preferably 1 mol% or more and 10 mol% or less, further preferably 1.5 mol% or more and 6.5 mol% or less, further preferably 5.2 mol% or more and 6.2 mol% or less, and the monomer unit derived from a (meth) acrylic acid may be contained in an amount of preferably more than 0.15 mol% and 5 mol% or less, more preferably 0.2 mol% or more and 4.5 mol% or less, further preferably 0.26 mol% or more and 4 mol% or less, further preferably 0.3 mol% or more and 3 mol% or less, based on the whole monomer units constituting the polymer, Still more preferably 0.6 mol% or more and 1 mol% or less of a glutaric anhydride structural unit. The (meth) acrylate is preferably methyl (meth) acrylate.

(B) Phosphorus-containing antioxidants

The polymer composition of the present invention may comprise a phosphorus containing antioxidant. Examples of the phosphorus-containing antioxidant include: mono-, di-or tri-phosphites (e.g., phenyl, diphenyl, triphenyl phosphite, etc.), tris (2, 4-di-tert-butylphenyl) phosphite, 2- [ [2,4,8, 10-tetrakis (1, 1-dimethylethyl) dibenzo [ d, f ] [1,3,2] dioxaphosphepin-6-yl ] oxy ] -N, N-bis [2- [ [2,4,8, 10-tetrakis (1, 1-dimethylethyl) dibenzo [ d, f ] [1,3,2] dioxaphosphepin-6-yl ] oxy ] ethyl ] ethylamine, diphenyltridecylphosphite, triphenyl phosphite, 2-methylenebis (4, 6-di-tert-butylphenyl) octylphosphite, diphenyliodobenzene, or diphenyliodobenzene, Pentaerythritol diphosphite bis (2, 6-di-tert-butyl-4-methylphenyl) ester, pentaerythritol distearate, neopentane tetrapentayl cyclic phosphite bis (2, 6-di-tert-butyl-4-methylphenyl) ester, tetrakis (2, 4-di-tert-butylphenyl) 4,4 '-biphenylene diphosphonite or tetrakis (2, 4-di-tert-butyl-5-methylphenyl) 4, 4' -biphenylene diphosphonite, and the like. Commercially available phosphorus-containing antioxidants may also be used, and examples thereof include: irgafos168 (tris (2, 4-di-tert-butylphenyl) phosphite, manufactured by BASF Japan K.K.), Sumilizer GP ((6- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propoxy ] -2,4,8, 10-tetra-tert-butylbenzo [ d, f ] [1,3,2] dioxaphosphepin, manufactured by Sumitomo chemical Co., Ltd.), JPP100 (tetraphenyl dipropylene glycol diphosphite, manufactured by North City chemical industries, Ltd.), JPH3800 (hydrogenated bisphenol-A-pentaerythritol phosphite polymer, manufactured by North chemical industries, Ltd.), Irgafos12 (tris [2- [ [2,4,8, 10-tetra-tert-butylbenzo [ d, f ] [1,3,2] dioxocycloheptadien-6-yl ] oxy ] ethyl ] amine, manufactured by basf japan), Irgafos38 (ethyl phosphite bis (2, 4-di-tert-butyl-6-methylphenyl) ester, manufactured by basf japan), ADEKA STAB HP-10 (octyl 2, 2' -methylenebis (4, 6-di-tert-butylphenyl) phosphite, manufactured by ADEKA corporation), ADEKA tab PEP36 (di (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, manufactured by ADEKA corporation), ADEKA STAB PEP36A (pentaerythritol diphosphite bis (2, 6-di-t-butyl-4-methylphenyl) ester, manufactured by ADEKA corporation), ADEKA tab PEP-8 (neopentanotetrayl cyclic phosphite bis (2, 4-di-t-butylphenyl) ester, manufactured by ADEKA corporation), HostanoxP-EPQ (PEPQ: tetrakis (2, 4-di-tert-butylphenyl) 4,4 '-biphenylene diphosphonite, manufactured by clariant corporation), GSY-P101 (tetrakis (2, 4-di-tert-butyl-5-methylphenyl) 4, 4' -biphenylene diphosphonite, manufactured by sakai chemical industry co. The phosphorus-containing antioxidant may be contained in the polymer composition of the present invention in a proportion of preferably 0.2 part by mass or less, more preferably 0.15 part by mass or less, further preferably 0.10 part by mass or less, further preferably 0.09 part by mass or less, and very preferably 0.08 part by mass or less, relative to 100 parts by mass of the polymer contained in the present invention. The lower limit of the phosphorus-containing antioxidant is not particularly limited, and is, for example, 0.005 parts by mass or more, preferably 0.01 parts by mass or more, and more preferably 0.05 parts by mass or more.

(C) Other ingredients

The polymer composition of the present invention may comprise, for example, other antioxidants, light stabilizers, lubricants, bluing agents, flame retardants, etc., in addition to the polymer, phosphorus-containing antioxidant. The molded article comprising the polymer composition of the present invention can be imparted with a coloring prevention effect, a weather resistance effect, a mold release effect and a yellowness index lowering effect. Further, a trace amount of components (residues of additives such as a polymerization initiator, a polymerization stabilizer, and a molecular weight regulator) which are inevitably mixed in the production process may be contained.

< monomer containing >

When the polymer composition A or the polymer composition B of the present invention is molded under the following injection conditions into a flat plate of 120mm × 100mm × 3.0mm in thickness, the difference (hereinafter also referred to as monomer content increase) between the monomer content in the flat plate comprising the polymer composition obtained under the condition that the cooling time in the mold is 5 minutes (hereinafter also referred to as 5 minute period) and the monomer content in the flat plate comprising the polymer composition obtained under the condition that the cooling time in the mold is 1 minute (hereinafter also referred to as 1 minute period) is 1000 mass ppm or more and 12000 mass ppm or less,

the injection conditions were:

(1) using a non-vented injection molding machine;

(2) a cold runner type mold;

(3) the temperature of the charging barrel is 260 ℃; and

(4) the ratio of the injection volume of the injection molding machine to the volume of the molded article was 4.5.

Here, the non-vented injection molding machine is an injection molding machine in which a cylinder part of the injection molding machine is not provided with a vent opening, and water, volatile gas including monomers, and the like contained in the polymer composition are not vented from the vent opening, and examples thereof include eC130SXII-4A manufactured by toshiba corporation. The cold runner system is a runner system in which a runner is cooled in a mold and taken out together with a molded product. The volume of the molded article means the volume of the polymer composition injected per 1 injection of the molded article including the gate and the runner, and the injection volume of the injection molding machine means the maximum volume of the polymer composition filled in the cylinder of the injection molding machine. The ratio of the injection volume of the injection molding machine to the volume of the molded product is 4.5, which means that the ratio is in the range of 4.45 to 4.54. The runner type of these molds and the ratio of the injection volume of the injection molding machine to the volume of the molded article affect the thermal history of the polymer composition during molding. Further, the cylinder temperature of 260 ℃ means the following conditions: the heater conditions of the injection molding machine were set to: the heaters from the raw material inlet (hopper) to the outlet were set to 55 to 65 ℃ from the raw material inlet, 220 to 230 ℃ near (downstream of) the heater under the hopper, 250 to 260 ℃ as the nozzle heater, and 260 ℃ as the temperature conditions for the other heaters.

It is generally known to those skilled in the art that a low monomer content in the molded article is advantageous in view of the physical properties of the molded article, but it has been found that by setting the increased amount of the monomer content within the above range, a molded article excellent in optical characteristics and heat resistance can be obtained.

In the present specification, the increase in the monomer content refers to a value obtained by subtracting the monomer content in the molded article produced under the condition of a1 minute cycle from the monomer content in the molded article produced under the condition of a 5 minute cycle.

In the present specification, the barrel temperature refers to the set temperature of the extruder, but generally the temperature of the polymer composition in the barrel is the same as the set temperature, and therefore the temperature of the polymer composition can be regarded as the set temperature of the extruder.

The linear velocity of the polymer composition at the nozzle tip at the time of molding is usually carried out in the range of 3.6 m/sec to 14.2 m/sec. The screw rotation speed during metering in injection molding is usually 20rpm to 80rpm, and the gate cross-sectional area of the mold is usually 20mm²～30mm²The gate position is usually 1 to 2.

The monomer contained in the molded article made of the polymer composition of the present invention means a raw material monomer remaining in the molded article in an unpolymerized state and a monomer contained in the molded article by decomposition of a polymer by heat at the time of granulation or injection molding. The monomer content in the shaped bodies can be determined, for example, by gas chromatography.

When the increase in the monomer content is 1000ppm by mass or more, the yellowness index of a molded article made of the polymer composition can be reduced, and the total light transmittance of the molded article can be improved. Specifically, the yellowness of a molded article produced under the condition of a 5 minute cycle using the polymer composition of the present invention can be adjusted to preferably 17.4 or less, more preferably 13.6 or less, further preferably 12.8 or less, further preferably 11.1 or less, further preferably 8.9 or less, further preferably 7.8 or less, and further preferably 5.9 or less. And the total light transmittance of the molded article produced under the condition of a 5 minute cycle can be adjusted to preferably 75.1% or more, more preferably 78.6% or more, further preferably 79.0% or more, further preferably 80.5% or more, further preferably 81.2% or more, further preferably 82.0% or more, further preferably 83.6% or more. Further, the yellowness of a molded article produced under the condition of a cycle of 1 minute using the polymer composition of the present invention can be adjusted to preferably 9.9 or less, more preferably 9.3 or less, further preferably 8.5 or less, further preferably 8.1 or less, further preferably 6.2 or less, further preferably 5.5 or less, further preferably 5.0 or less. And the total light transmittance of the molded article produced under the condition of a1 minute cycle can be adjusted to preferably 79.6% or more, more preferably 80.2% or more, further preferably 81.0% or more, further preferably 83.7% or more, further preferably 84.0% or more, further preferably 84.5% or more. The yellowness and total light transmittance of the molded article can be measured, for example, using a spectrophotometer.

When the increase in the monomer content is 12000ppm by mass or less, a molded article made of the polymer composition can have sufficient heat resistance. Specifically, the vicat softening temperature of a molded article produced under the condition of a period of 5 minutes using the polymer composition of the present invention can be adjusted to preferably 107 ℃ or higher, more preferably 108 ℃ or higher. In particular, the reduction in vicat softening temperature between a molded article produced under the condition of a 5 minute cycle and a molded article produced under the condition of a1 minute cycle can be adjusted to preferably 9.7 ℃ or less, more preferably 7.5 ℃ or less, and still more preferably 5.0 ℃ or less, and extreme reduction in heat resistance due to a difference in cycle time can be prevented. The Vicat softening temperature of the molded article can be measured, for example, in accordance with JIS K7206 (method B50).

When the increase in the monomer content is 12000 mass ppm or less, the yellowness of the molded article when it is left at 120 ℃ for 400 hours can be adjusted to preferably 46.1 or less, more preferably 40.0 or less, further preferably 30.0 or less, further preferably 18.5 or less, further preferably 6.2 or less, further preferably 5.5 or less, and good heat deterioration resistance can be obtained. The heat deterioration resistance of the polymer composition is evaluated by yellowness, and can be measured, for example, by a spectrophotometer.

The increase in the monomer content is 1000 mass ppm or more and 12000 mass ppm or less, preferably 2000 mass ppm or more and 11500 mass ppm or less, more preferably 6000 mass ppm or more and 11000 mass ppm or less, still more preferably 7000 mass ppm or more and 10800 mass ppm or less, and still more preferably 8000 mass ppm or more and 10600 mass ppm or less.

The above-mentioned increase in the monomer content is influenced by various conditions. For example, by setting the content of the cyclic structural monomer unit within the above range, the increase in the monomer content can be adjusted to be within the above-specified range. Specifically, as described above, the cyclic structure monomer unit is contained in the polymer preferably in a proportion of more than 0.15 mol% and not more than 5 mol%, more preferably in a proportion of 0.2 mol% or more and not more than 4.5 mol%, further preferably in a proportion of 0.26 mol% or more and not more than 4 mol%, further preferably in a proportion of 0.3 mol% or more and not more than 3 mol%, and further preferably in a proportion of 0.6 mol% or more and not more than 1 mol%, relative to the total monomer units. By adjusting the cyclic structure monomer unit in the polymer within the above range, the amount of increase in the monomer content can be increased, and the possibility of the increase in the monomer content being less than 1000 mass ppm can be reduced. The content of the ring structure monomer unit can be adjusted by the proportion (mol% or mass%) of the monomer having a ring structure or the monomer forming a ring structure in the raw material, the temperature at the time of extrusion granulation, and the accelerator for the ring structure forming reaction added at the time of extrusion granulation.

Further, the amount of the phosphorus-containing antioxidant to be mixed may also affect the amount of increase in the monomer content. For example, by setting the upper limit of the amount of the phosphorus-containing antioxidant to preferably 0.2 parts by mass or less, more preferably 0.15 parts by mass or less, further preferably 0.1 parts by mass or less, further preferably 0.09 parts by mass or less, and very preferably 0.08 parts by mass or less, and setting the lower limit of the amount of the phosphorus-containing antioxidant to preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and further preferably 0.05 parts by mass or more, an increase in the amount of increase in the monomer content can be suppressed. By suppressing the increase in the monomer content, excellent heat resistance can be imparted to the molded article. The molded article has more excellent heat resistance, and is useful as a material for an optical member of an optical lens of a high-brightness LED lamp, which particularly requires high heat resistance.

The polymer composition of the present invention may have an MFR (melt flow rate) value of preferably 0.1g/10 min or more and 10g/10 min or less, more preferably 1g/10 min or more and 6g/10 min or less, still more preferably 2g/10 min or more and 5g/10 min or less, and still more preferably 2.5g/10 min or more and 4g/10 min or less under a load of 3.8kg at 230 ℃. By adjusting the MFR to such a value, when the polymer composition is used as a raw material for an optical member such as an optical lens, appropriate fluidity is exhibited, for example, when the polymer composition is injection molded or the like. In the present specification, the MFR value can be measured according to the method defined in JIS K7210.

The weight average molecular weight of the polymer contained in the polymer composition of the present invention may be preferably 50000 or more and 120000 or less, more preferably 60000 or more and 100000 or less, and further preferably 70000 or more and 90000 or less. By adjusting the weight average molecular weight to such a value, the mechanical properties of the molded article made of the polymer composition of the present invention can be improved. The weight average molecular weight of the polymer can be measured, for example, by gel permeation chromatography.

The glass transition temperature (Tg) of the polymer composition of the present invention may be in the range of preferably 115 ℃ or more and 130 ℃ or less, more preferably 120 ℃ or more and 126 ℃ or less. The water absorption of the polymer composition of the present invention may be in the range of preferably 0.1% by weight or more and 0.5% by weight or less, more preferably 0.2% by weight or more and 0.4% by weight or less. The glass transition temperature of the polymer composition of the present invention can be measured, for example, by Differential Scanning Calorimetry (DSC) in accordance with JIS K7121, and the water absorption can be measured by a method in accordance with JIS K7209.

< method for producing Polymer composition >

In the method for producing the polymer composition of the present invention, first, two or more kinds of monomers as raw materials are polymerized, and if necessary, other components are added to obtain the polymer composition a or the polymer composition B. The method of polymerizing the monomer is not particularly limited, and for example, a known polymerization method such as suspension polymerization, solution polymerization, bulk polymerization, or the like can be used. In particular, suspension polymerization may be employed. The suspension polymerization can be carried out, for example, in the following manner: water, a polymerization initiator, a chain transfer agent, a suspension stabilizer, and other additives as necessary are charged into an autoclave, and the monomer components are usually supplied and heated under stirring. The amount of water used is usually about 1 to about 5 times, particularly about 1 to about 3 times, the amount of the monomer component in terms of volume ratio.

The polymerization initiator is not particularly limited, and for example, peroxides such as lauryl peroxide and 1, 1-di (t-butylperoxy) cyclohexane; and known radical polymerization initiators such as azo compounds, e.g., azobisisobutyronitrile. The polymerization initiator may be one kind or two or more kinds.

The chain transfer agent is not particularly limited, and examples thereof include: mercaptans such as n-dodecylmercaptan (particularly 1-dodecylmercaptan), n-butylmercaptan, n-octylmercaptan, and 2-ethylhexyl thioglycolate. The chain transfer agent may be one kind or two or more kinds.

As the suspension stabilizer, for example, there can be mentioned: water-soluble cellulose ethers such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose. In addition, partially saponified vinyl alcohol, acrylic acid polymers, and water-soluble polymers such as gelatin may also be used.

In the suspension polymerization, for example, a slurry-like reaction product obtained after the polymerization is dehydrated, washed as necessary, and then dried. After drying, a bead-like polymer composition A or polymer composition B is obtained. The bead-shaped polymer composition A or the polymer composition B may be used as it is, or other components as described above may be added. When the polymer composition a or the polymer composition B and other ingredients added as needed are further extruded by means of an extruder (e.g., a degassing extruder), the polymer composition of the present invention in the form of pellets is obtained.

More specifically, the polymer composition of the present invention is a polymer composition a including a polymer of a monomer having a ring structure, or a polymer composition which is a cyclization product of a polymer composition B including a precursor polymer which is a polymer of two or more monomers capable of forming a ring together and which can be obtained by extruding the polymer composition a or the polymer composition B by an extruder having a cylinder temperature of usually 200 ℃ or more and less than 280 ℃, preferably 220 ℃ or more and 275 ℃ or less, more preferably 240 ℃ or more and 270 ℃ or less. By setting the cylinder temperature within the above range, the amount of increase in monomer content can be easily adjusted within the above specified range, and as a result, the value of yellowness of a molded article made of the polymer composition can be particularly reduced. In particular, by setting the cylinder temperature to less than 280 ℃, the possibility of an increase in the monomer content of less than 1000 mass ppm can be reduced, and as a result, the value of yellowness of a molded article composed of the polymer composition can be particularly reduced, and the total light transmittance can also be improved.

In the method for producing a polymer composition of the present invention, when the polymer composition of the present invention is produced from the polymer composition B, the method may further comprise a step of cyclizing two or more monomer units capable of forming a ring together by extrusion in an extruder.

As described above, by adjusting the increase in the monomer content of the molded article produced from the polymer composition of the present invention to the above-specified range, the molded article has a particularly low yellowness value and sufficient heat resistance. For example, by containing more monomers having a fast reaction speed as the raw material monomers for the polymerization reaction, the monomer content under the conditions of the 1 minute period and the 5 minute period can be reduced. Further, for example, by selecting a polymerization method having a higher monomer polymerization rate such as suspension polymerization, the monomer content under the conditions of the 1 minute period and the 5 minute period can be reduced. In addition, the monomer content under the conditions of the 1 minute cycle and the 5 minute cycle can be increased by employing polymerization conditions such as shortening the polymerization time and reducing the amount of the polymerization initiator added.

In the method for producing the polymer composition of the present invention, it is preferable to set the cycle time in the injection molding machine to an appropriate time without excessively increasing the barrel temperature of the extruder. For example, when the screw rotation speed of the extruder is preferably 100rpm or more and 400rpm or less, more preferably 200rpm or more and 300rpm or less, the treatment amount is preferably 5 kg/hour or more and 20 kg/hour or less, and more preferably 10 kg/hour or more and 17 kg/hour or less, in terms of the treatment amount of the composition per cycle time in the extruder. Alternatively, for example, the post-treatment may not be heated at an elevated temperature (e.g., about 290 ℃) for an extended period of time. By appropriately selecting and setting the production conditions in this manner, it is possible to prevent the physical properties from being significantly changed. As a result, the yellowness index of the molded article can be reduced, and the molded article can have sufficient heat resistance.

< molded body and optical Member >

The molded article composed of the polymer composition of the present invention can be appropriately shaped according to the intended use. The molded article can be obtained by injection-filling the polymer composition of the present invention. Specifically, as described above, the polymer composition of the present invention is granulated, and is charged into a cylinder from a hopper, the polymer composition is melted while rotating a screw, a predetermined amount of the polymer composition is filled into the cylinder by moving the screw backward, the melted polymer composition is injection-filled into a mold while applying pressure by moving the screw forward, the pressure is maintained for a certain period of time until the mold is sufficiently cooled, and then the mold is opened and the molded body is taken out, whereby a molded body can be obtained. The conditions for producing the molded article (for example, the melting temperature of the molding material in the cavity, the mold temperature when the molding material is injected into the mold, the pressure when the pressure is maintained after the polymer composition is filled into the mold) are not particularly limited as long as they are appropriately set.

An optical member can be produced using a molded article composed of the polymer composition of the present invention. Therefore, the optical member has a low yellowness value and has heat resistance. The optical member refers to an optical lens, a light guide member, and the like. For example, the optical member refers to an optical lens, a light guide member, or the like that can be used in general illumination equipment such as a lamp for an automobile or a motorcycle, a street lamp, a desk lamp, or general illumination for home use.

Examples

The present invention will be described more specifically with reference to the following examples and comparative examples, but the present invention is not limited thereto.

In the present specification, the "methacrylic polymer composition" refers to a composition containing a polymer obtained by polymerizing at least a part of one or more monomers selected from the group consisting of methacrylic acid and methacrylic acid esters. In addition, the following describes methods for measuring physical properties of the polymer composition and its test molded piece (molded article), and the physical properties and measurements (or physical property values and measured values) described in the present specification including examples are based on values obtained by the following methods.

Preparation of methacrylic Polymer composition and preparation of test molded sheet

(example 1)

In a 5L autoclave equipped with a stirrer, 5 parts by mass of methacrylic acid (hereinafter referred to as MAA, manufactured by japan catalyst co., ltd.) and 95 parts by mass of methyl methacrylate (hereinafter referred to as MMA, manufactured by sumitomo chemical co., ltd.) were mixed to obtain a monomer component. In the monomer components, 0.4 part by mass of lauryl peroxide (Laurox K manufactured by Kayaku Akzo Co., Ltd.) as a polymerization initiator and 0.6 part by mass of 1-dodecylmercaptan as a chain transfer agent were added and dissolved, relative to 100 parts by mass of the total of the monomer components. Then, 0.060 parts by mass of hydroxyethylcellulose (hereinafter referred to as HEC, "sanhe c", manufactured by mitcham corporation) as a suspension stabilizer was dissolved in ion-exchanged water with respect to 100 parts by mass of the total of the monomer components to prepare a suspension polymerization aqueous phase, and 150 parts by mass of the aqueous phase was added to 100 parts by mass of the total of the monomer components to perform suspension polymerization. The obtained slurry-like reaction solution was dehydrated by a dehydrator ("centrifuge H-122" manufactured by KOKUSAN corporation) and washed 2 times with 40L of ion-exchanged water, and then dried to obtain a bead-like polymer composition. To 100 parts by mass of the polymer composition, 0.06 parts by mass of a phosphorus-containing antioxidant (Sumilizer GP, manufactured by Sumitomo chemical Co., Ltd.) was mixed, and the resulting mixture was melt-kneaded under the following kneading conditions using a twin-screw extruder (type: TEX30SS-30AW-2V), manufactured by Nippon Steel works, and extruded into strands, which were then water-cooled and cut with a strand cutter to obtain a granular methacrylic polymer composition.

(mixing Condition)

Extruder temperature: 240 ℃ (for 8 heaters from the raw material input port to the output port, the raw material input port is set as 210 ℃, 220 ℃, 240 ℃, 255 ℃ respectively)

Rotating speed: 250rpm

Raw material input speed: 10 kg/hour

The obtained methacrylic polymer composition in a pellet form was molded into a flat plate shape of 120mm × 100mm × 3.0mm in thickness under the following molding conditions under a cooling timer of 1 minute (i.e., 1 minute period) and under a cooling timer of 5 minutes (i.e., 5 minute period) for each sample using a non-vented injection molding machine (eC 130SXII-4A manufactured by toshiba mechanical corporation, nozzle diameter of 3mm), to obtain a test molded piece.

(Molding conditions)

Barrel temperature: 260 ℃ is set to 60 ℃ (heater under hopper), 225 ℃ (H3), 260 ℃ (H2), 260 ℃ (H1), and 255 ℃ (nozzle heater) for five heaters from the raw material inlet (hopper) to the outlet as shown in FIG. 1

Ratio of injection volume of injection molding machine to volume of molded product: 4.5

Screw diameter: 40mm

Injection speed: 50 mm/sec

Linear velocity at nozzle: 7.1 m/s

Maximum injection pressure: 110MPa

Maintaining the pressure: 60MPa

Maintaining the pressure velocity: 20 mm/sec

An injection timer: 8 seconds

Temperature of the die: 60 deg.C

The flow channel mode is as follows: cold runner

And (3) gate position: 1 position

Gate cross-sectional area: 24mm²(width 8 mm. times. height 3mm)

A cooling timer: condition 1)60 seconds; condition 2)300 seconds

Screw rotation speed during metering: 40rpm

Back pressure: 10 percent of

(examples 2 and 3)

A methacrylic polymer composition and test molded pieces under conditions of a 1-minute cycle and a 5-minute cycle were obtained in the same manner as in example 1, except that the amount of the phosphorus-containing antioxidant (manufactured by sumitomo chemical corporation, "Sumilizer GP") mixed in the polymer composition in the form of beads was 0.08 parts by mass or 0.10 parts by mass, respectively.

(example 4)

A methacrylic polymer composition and test molded pieces under conditions of a 1-minute cycle and a 5-minute cycle were obtained in the same manner as in example 3, except that the phosphorus-containing antioxidant incorporated in the polymer composition in the form of beads was a phosphorus-containing antioxidant ("Irgafos 168", manufactured by basf japan).

(example 5)

The same operation as in example 1 was carried out except that the polymerization composition of the finally obtained methacrylic polymer composition was changed by changing the mixing ratio of MAA and MMA to 4 parts by mass and 96 parts by mass, respectively, of MAA and MMA, which were charged into and mixed with the autoclave (see table 1 shown below), and the amount of the phosphorus-containing antioxidant (Sumilizer GP, manufactured by sumitomo chemical corporation) mixed into the polymer composition in the form of beads was 0.05 part by mass, thereby obtaining a methacrylic polymer composition and a test molded piece under the conditions of 1 minute cycle and 5 minute cycle.

(examples 6 to 8)

A methacrylic polymer composition and test molded pieces in a 1-minute cycle and a 5-minute cycle were obtained in the same manner as in example 5, except that the amount of the phosphorus-containing antioxidant mixed in the polymer composition in the form of beads was 0.07 parts by mass, 0.15 parts by mass, or 0.03 parts by mass (Irgafos 168, manufactured by basf japan).

Comparative example 1

A methacrylic polymer composition and test molded pieces under the conditions of a1 minute cycle and a 5 minute cycle were obtained in the same manner as in example 1, except that the phosphorous antioxidant was not mixed in the polymer composition in the form of beads.

Comparative example 2

A methacrylic polymer composition and test molded pieces under conditions of a 1-minute cycle and a 5-minute cycle were obtained in the same manner as in example 5, except that the amount of the phosphorus-containing antioxidant (manufactured by sumitomo chemical corporation, "Sumilizer GP") mixed in the polymer composition in the form of beads was changed to 0.30 parts by mass.

Comparative example 3

The same operation as in example 5 was carried out except that the amount of the phosphorus-containing antioxidant (Irgafos 168, manufactured by BASF Japan) mixed in the polymer composition in the form of beads was 0.25 part by mass, to obtain a methacrylic polymer composition and test molded pieces under the conditions of a 1-minute cycle and a 5-minute cycle.

Comparative example 4

A methacrylic polymer composition and test molded pieces were obtained in the same manner as in example 5 except that kneading conditions were set as described above when a twin-screw extruder (model No. TEX30SS-30AW-2V) manufactured by Nippon Steel works was used.

Extruder temperature: 280 deg.C (for 8 heaters from the raw material inlet to the outlet, 210 deg.C, 220 deg.C, 280 deg.C, respectively from the raw material inlet side.)

Comparative example 5

A polymer composition was obtained in the same manner as in example 6, except that the MAA and the MMA were charged into and mixed in the autoclave in an amount of 90 parts by mass and 10 parts by mass, respectively, and that 0.05 parts by weight of a 25 wt% aqueous sodium hydroxide solution and 0.05 parts by weight of a phosphorus-containing antioxidant (Sumilizer GP, manufactured by sumitomo chemical corporation) were added to 100 parts by mass of the polymer composition in the form of beads, respectively. A methacrylic polymer composition and test molded pieces under conditions of a1 minute cycle and a 5 minute cycle were obtained in the same manner as in example 5, except that the polymerization composition of the finally obtained methacrylic polymer composition (see table 1 shown below) was changed.

Analysis and determination

< analysis of polymerization composition of methacrylic Polymer composition >

Measured by using a nuclear magnetic resonance apparatus ("Avance 600" (10mm cryoprobe) manufactured by Bruker Co., Ltd.)¹³The polymerization compositions of the methacrylic polymer compositions obtained in examples 1 to 8 and comparative examples 1 to 5 were analyzed by C-NMR. The measurement solvent used was deuterated chloroform, the measurement temperature was set at 27 ℃, and the measurement was performed by the reverse gated decoupling method. The pulse repetition time was set to 20 seconds, the number of times of accumulation was set to 4000 times, and the chemical shift value was set to chloroform. The MMA value was determined from the integrated value of the peaks from 173.0ppm to 180.4 ppm. The MAA value was determined from the integral value of the peak at 180.4ppm to 188.0 ppm. The value of the glutaric anhydride structure (hereinafter also referred to as GAH) formed by cyclized condensation of MMA and MAA was determined from the integrated value of the peaks at 170.0ppm to 173.0 ppm.

< measurement of Heat deterioration resistance of methacrylic Polymer composition >

The methacrylic polymer compositions obtained in examples 1 to 8 and comparative examples 1 to 5 were evaluated for heat deterioration resistance. The obtained methacrylic polymer composition in the form of pellets was dried at 80 ℃ for 12 hours and then press-molded at a pressing temperature of 220 ℃ using a press molding machine (Shinto type ASF hydraulic press, manufactured by Shenteng Metal industries Co., Ltd.), to obtain test pieces of 50mm X3 mm. Next, each of the obtained test pieces was allowed to stand for 400 hours in a thermostat (Perfect Oven "PH-101" manufactured by Espec corporation) set at a temperature of 120 ℃. The yellowness of the test pieces before and after the test at an optical path length of 50mm was measured using a spectrophotometer ("Hitachi spectrophotometer U-4000" manufactured by Hitachi high New technology Co., Ltd.).

< measurement of Total light transmittance (Tt) of test molded piece >

The total light transmittance was measured for each test molded piece obtained under the conditions of the 1 minute period and the 5 minute period of the methacrylic polymer compositions obtained in examples 1 to 8 and comparative examples 1 to 5. The total light transmittance was measured in the range of 380nm to 780nm at an optical path length of 100mm using a spectrophotometer ("Hitachi spectrophotometer U-4000" manufactured by Hitachi high tech Co., Ltd.).

< measurement of yellowness (yellowness index (YI)) of test molded pieces >

The yellowness was measured for each test molded piece obtained under the conditions of a1 minute cycle and a 5 minute cycle of the methacrylic polymer compositions obtained in examples 1 to 8 and comparative examples 1 to 5. The yellowness index of the resultant film was measured in the range of 380nm to 780nm at an optical path length of 100mm using a spectrophotometer ("Hitachi spectrophotometer U-4000" manufactured by Hitachi high and New technology Co., Ltd.).

< measurement of Vicat Softening Temperature (VST) of test molded piece >

Vicat softening temperatures were measured for each of the test molded pieces obtained under the conditions of the 1 minute cycle and the 5 minute cycle of the methacrylic polymer compositions obtained in examples 1 to 8 and comparative examples 1 to 5. The Vicat softening temperature (. degree.C.) was measured according to JIS K7206 (method B50) using an injection-molded sheet of the obtained methacrylic polymer composition using a heat distortion tester (manufactured by Katsuka corporation, "148-6 series").

< measurement of monomer content in test molded piece >

The monomer contents, that is, the amounts of MMA monomer and MAA monomer were measured for each of the test molded pieces obtained under the conditions of 1-minute cycle and 5-minute cycle of the methacrylic polymer compositions obtained in examples 1 to 8 and comparative examples 1 to 5.

(sample preparation)

As shown in FIG. 2, a test piece of the obtained polymer composition was cut out by 2.5cm X10 cm from a portion on the side opposite to the gate side, 2.5g thereof was precisely weighed, and 10cc of acetone (special grade) was added. After completely dissolving the mixture, 1cc of an internal standard solution (a solution obtained by dissolving 1% methyl isobutyl ketone (MIBK) in methanol) was added thereto, and the mixture was sufficiently stirred. Then, 30cc of methanol was added to reprecipitate the copolymer, and then the supernatant was collected.

(measurement conditions)

The device comprises the following steps: GC-2010Plus (manufactured by Shimadzu corporation)

Column: DB-1 (Agilent science and technology company)

A detector: FID 2010Plus (manufactured by Shimadzu corporation)

Column oven conditions (MMA monomer)

Initial temperature: 40 deg.C (hold time 1 minute)

Temperature rise rate: 8 ℃ per minute

Intermediate temperature: 120 deg.C (hold time 0 min)

Temperature rise rate: 20 ℃ per minute

Final temperature: 250 ℃ (holding time 5 minutes)

Column oven conditions (MAA monomer)

Initial temperature: 80 ℃ (holding time 3 minutes)

Temperature rise rate: 10 ℃/min

Final temperature: 300 deg.C (hold time 5 minutes)

Sample vaporization conditions (MMA monomer)

Temperature of the gasification chamber: 300 deg.C

Carrier gas: helium gas

Pressure: 50kPa

Total flow rate: 58.3 mL/min

Column flow rate: 1.08 mL/min

Linear velocity: 31.1 cm/sec

Purge line rate: 3.0 mL/min

The split ratio is as follows: 50

Sample vaporization conditions (MAA monomer)

Temperature of the gasification chamber: 300 deg.C

Carrier gas: helium gas

Pressure: 64kPa

Total flow rate: 124.3 mL/min

Column flow rate: 1.20 mL/min

Linear velocity: 36.6 cm/sec

Purge line rate: 3.0 mL/min

The split ratio is as follows: 100

Detector condition

Detector temperature: 300 deg.C

Sampling rate: 40 milliseconds

Tail blowing: n is a radical of₂

Tail gas blowing flow: 30 mL/min

H₂Flow rate: 40 mL/min

Air flow rate: 400 mL/min

Autosampler conditions

Sample introduction amount: 1 μ L

The peak area (a1) corresponding to the MMA monomer or MAA monomer and the peak area (b1) corresponding to MIBK detected when the respective polymer compositions were measured under the above-described conditions were measured. Then, from these peak areas, a peak area ratio a (═ a1/b1) was determined.

On the other hand, the peak area (a0) corresponding to the MMA monomer or MAA monomer and the peak area (b0) corresponding to MIBK detected when the weight ratio of MIBK to the MMA monomer or MAA monomer, W0 (known) was measured under the above conditions were measured, and the peak area ratio a0 (a 0/b0) was determined from these peak areas.

Then, from the peak area ratio a0 and the weight ratio W0, the factor f (═ W0/a0) was determined for each of the MMA monomer and the MAA monomer.

Then, the weight ratio W of the MMA monomer or MAA monomer contained in the polymer composition to be measured with respect to MIBK was determined by multiplying the peak area ratio a by the factor f, and the ratio (ppm) of the MMA monomer or MMA monomer in the injection-molded sheet was calculated from the weight ratio W and the weight of the injection-molded sheet of the polymer composition used in the analysis.

The results of analysis of the polymerization compositions and the results of evaluation of the thermal deterioration resistance characteristics of the polymer compositions of examples 1 to 8 and comparative examples 1 to 5 and the results of measurement of the test molded pieces are shown in table 1 below. In addition, the value obtained by subtracting the physical property value of the test molded piece produced under the condition of the 1 minute cycle from the physical property value of the test molded piece produced under the condition of the 5 minute cycle, and the difference between the monomer content in the test molded piece produced under the condition of the 5 minute cycle and the monomer content in the test molded piece produced under the condition of the 1 minute cycle are shown.

As is clear from Table 1 above, in examples 1 to 8 in which the increase in monomer content was in the range of 1000ppm or more and 12000ppm, the yellowness of the molded article produced under the condition of 1 minute cycle and the molded article produced under the condition of 5 minute cycle was suppressed, and the heat resistance was sufficient. On the other hand, comparative examples 1, 4 and 5, in which the increase of the monomer content was 1000ppm or less, had high yellowness and insufficient transparency. In comparative examples 2 and 3 in which the increase in the monomer content was 12000ppm or more, the molded articles molded under the condition of the cycle time of 5 minutes in particular had a low Vicat softening temperature and insufficient heat resistance and heat deterioration resistance.

Industrial applicability

The molded article composed of the polymer composition of the present invention has low yellowness and high heat resistance. Therefore, the molded article can be suitably used as an optical lens or a light guide member, and can be suitably used for, for example, a lamp for an automobile or a motorcycle, a street lamp, a table lamp, general illumination equipment such as general illumination for home use, and the like.

Description of the reference symbols

1: nozzle heater

2: h1 heater

3: h2 heater

4: h3 heater

5: heater under hopper

6: hopper

7: nozzle with a nozzle body

8: test molded piece

9: pouring gate

10: cutting off the part