阅读说明：本技术 聚缩醛共聚物和其制造方法 (Polyacetal copolymer and method for producing same ) 是由 喜来直裕 增田荣次 于 2019-12-05 设计创作，主要内容包括：本发明的目的在于,通过导入具有新型结构的基团从而提供生产率、机械特性优异的新型聚缩醛共聚物和其制造方法。本发明的目的通过如下聚缩醛共聚物而实现：其是至少使三氧杂环己烷和(A)式(1)所示的硅氧烷化合物共聚而得到的。(式(1)中,分别地R～1表示碳数1～6的一价脂肪族烃基或碳数6～10的芳香族烃基,X表示R～1或具有环氧基的有机基团。其中存在多个的X中的2个以上为具有环氧基的有机基团,存在多个的R～1、X任选分别相同或不同。)(The present invention aims to provide a novel polyacetal copolymer having excellent productivity and mechanical properties by introducing a group having a novel structure, and a method for producing the same. The object of the present invention is achieved by the following polyacetal copolymers: which is obtained by copolymerizing at least trioxane and (A) a siloxane compound represented by the formula (1). (in the formula (1), R is each 1 Represents a C1-6 monovalent aliphatic hydrocarbon group or C6-10 aromatic hydrocarbon group, X represents R 1 Or an organic group having an epoxy group. Wherein 2 or more of X's in the plural are organic groups having an epoxy group, and R's in the plural are present 1 And X are optionally the same or different. ))

1. A polyacetal copolymer obtained by copolymerizing at least trioxane and (A) a siloxane compound represented by the formula (1),

in the formula (1), R is independently¹Represents a C1-6 monovalent aliphatic hydrocarbon group or C6-10 aromatic hydrocarbon group, X represents R¹Or an organic group having an epoxy group, wherein 2 or more of X's in the plural are organic groups having an epoxy group, and R's in the plural are present¹And X are optionally the same or different.

2. The polyacetal copolymer according to claim 1, which is obtained by copolymerizing (B) a cyclic acetal compound having an oxyalkylene group having 2 or more carbon atoms in the ring.

3. The polyacetal copolymer according to claim 1 or 2, wherein the organic group having an epoxy group is a 2- (3, 4-cyclohexyl) ethyl group.

4. The polyacetal copolymers as claimed in claim 1 to 3, wherein the siloxane compound represented by the formula (A) is a compound (A-1) wherein Me represents a methyl group,

5. a method for producing a polyacetal copolymer, which comprises copolymerizing at least trioxane and a siloxane compound represented by the formula (1),

in the formula (1), R is independently¹Represents a C1-6 monovalent aliphatic hydrocarbon group or C6-10 aromatic hydrocarbon group, X represents R¹Or an organic group having an epoxy group, wherein 2 or more of X's in the plural are organic groups having an epoxy group, and R's in the plural are present¹And X are optionally the same or different.

Technical Field

The present invention relates to a novel polyacetal copolymer excellent in productivity and mechanical properties, and a method for producing the same.

Background

Polyacetal resins have excellent properties in terms of mechanical properties, thermal properties, electrical properties, slidability, moldability and the like, and are widely used mainly as structural materials, mechanical parts and the like for electrical equipment, automobile parts, precision machine parts and the like. However, as the field of application of polyacetal resins has expanded, the required properties have tended to be increasingly higher, more complex and more specialized. As such required properties, further improvement in mechanical strength is required while maintaining excellent slidability, appearance and the like inherent in polyacetal resins.

On the other hand, for the purpose of improving the rigidity, a method of filling a fibrous filler or the like into a polyacetal resin is generally used, but this method has problems such as poor appearance of a molded article, reduction in sliding characteristics, and the like due to filling of the fibrous filler or the like, and further has a problem of reduction in toughness.

Further, it is known that the rigidity of the polyacetal copolymer is improved without substantially impairing the slidability and the appearance by reducing the amount of the comonomer, but the method of reducing the comonomer causes problems such as not only a decrease in toughness but also a decrease in thermal stability of the polymer, and thus the method is not always satisfactory.

However, depending on the kind of the comonomer, when a cationic polymerization catalyst, particularly a protonic acid, is used as the polymerization catalyst, the initiation of polymerization may be delayed, and the polymerization may suddenly and explosively occur, and there is a problem in view of production stability.

For example, as for the polyacetal copolymer, a copolymer obtained by copolymerizing trioxane with a compound having 2 or more glycidyl ether groups in 1 molecule has been proposed (patent document 1). However, when a compound having a plurality of epoxy groups represented by glycidyl ether groups and ether oxygen groups as functional groups is used in polymerization, there remains a problem in polymerization stability. In particular, when a protonic acid is used as a polymerization catalyst, polymerization does not occur at a low catalyst amount, and when the catalyst amount is increased, a phenomenon occurs in which a sharp polymerization reaction suddenly occurs after an irregular induction period, and it is difficult to control the polymerization.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent application No. 2001-163944

Disclosure of Invention

Problems to be solved by the invention

The present invention aims to provide a novel polyacetal copolymer having excellent productivity and mechanical properties by introducing a group having a novel structure, and a method for producing the same.

Means for solving the problems

The object of the present invention is achieved as follows.

1. A polyacetal copolymer obtained by copolymerizing at least trioxane and (A) a siloxane compound represented by the formula (1).

(in the formula (1), R is each¹Represents a C1-6 monovalent aliphatic hydrocarbon group or C6-10 aromatic hydrocarbon group, X represents R¹Or an organic group having an epoxy group. Wherein 2 or more of X's in the plural are organic groups having an epoxy group, and R's in the plural are present¹And X are optionally the same or different. )

2. The polyacetal copolymer according to 1, which is obtained by further copolymerizing (B) a cyclic acetal compound having an oxyalkylene group having 2 or more carbon atoms in the ring.

3. The polyacetal copolymer according to 1 or 2, wherein the organic group having an epoxy group is a 2- (3, 4-cyclohexyl) ethyl group.

4. The polyacetal copolymers as set forth in any of the above 1 to 3, wherein the siloxane compound represented by the formula (1) of the above (A) is the following compound (A-1). In the formula (A-1), Me represents a methyl group.

5. A method for producing a polyacetal copolymer, wherein at least trioxane and a siloxane compound represented by the formula (1) are copolymerized.

(in the formula (1), R is each¹Represents a C1-6 monovalent aliphatic hydrocarbon group or C6-10 aromatic hydrocarbon group, X represents R¹Or an organic group having an epoxy group. Wherein 2 or more of X's in the plural are organic groups having an epoxy group, and R's in the plural are present¹And X are optionally the same or different. )

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there can be provided: a novel polyacetal copolymer excellent in productivity and mechanical properties and a process for producing the same.

Detailed Description

The present invention is not limited to the following embodiments, and can be carried out with appropriate modifications within the intended scope of the present invention.

< polyacetal copolymer >

The polyacetal copolymer of the present invention is characterized by being obtained by copolymerizing at least trioxane and (A) a siloxane compound represented by the formula (1).

The polyacetal copolymer of the present invention includes a siloxane structure having a plurality of reacted epoxy groups, and thus has excellent mechanical properties.

Trioxane

Trioxane used in the present invention is a cyclic trimer of formaldehyde, and is generally obtained by reacting an aqueous formaldehyde solution in the presence of an acidic catalyst, and is used by purifying it by a method such as distillation.

Siloxane Compound represented by the formula (A) formula (1)

The component (A) used in the present invention is characterized by being a siloxane compound represented by the formula (1).

(in the formula (1), R is each¹Represents a C1-6 monovalent aliphatic hydrocarbon group or C6-10 aromatic hydrocarbon group, X represents R¹Or an organic group having an epoxy group. Wherein 2 or more of X's in the plural are organic groups having an epoxy group, and R's in the plural are present¹And X are optionally the same or different. )

R¹Examples of the monovalent aliphatic hydrocarbon group include a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms and an aromatic hydrocarbon group having 6 to 10 carbon atoms, and include a saturated monovalent aliphatic hydrocarbon group such as an alkyl group such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, heptyl group, etc., an unsaturated monovalent aliphatic hydrocarbon group such as an alkenyl group such as a vinyl group, allyl group, isopropenyl group, butenyl group, etc., a phenyl group, naphthyl group, etc., preferably a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group.

The organic group in X is a compound formed of C, H, N, O atoms, specific examples of the epoxy group-containing organic group include a 2- (3, 4-cyclohexyl) ethyl group and a 3-glycidoxypropyl group, and a 2- (3, 4-cyclohexyl) ethyl group is preferable from the viewpoint of stability of the polymerization reaction. Here, the number of carbon atoms in the organic group is preferably 1 to 20, more preferably 3 to 15. From the viewpoint of stability of polymerization and mechanical strength, a 2- (3, 4-cyclohexyl) ethyl group via an alkylene group having 1 to 5 carbon atoms is preferable.

The siloxane compound of the formula (1) can be produced by a known method described in, for example, Japanese patent application laid-open Nos. 2010-229324 and 2016-204288. When these production methods are applied, a cyclic siloxane having a 6-membered ring, a 10-membered ring or a 12-membered ring in which 3,5 or 6 units of siloxane units are bonded may be formed as a by-product, but the presence of these units has little influence on the production of the polyacetal copolymer of the present invention, and it is sufficient if the cyclic siloxane having an 8-membered ring of the present invention is contained in an amount of 80% by mass or more.

The reason why the polymerization control is facilitated in the case of copolymerizing the siloxane compound of the formula (1) in the present invention is presumably because the epoxy group serving as a copolymerization reaction site is fixed to the outside of the molecule by the siloxane ring structure of the formula (1), and thus the reaction probability is increased.

Particularly preferred silicone compounds are the following compounds (A-1). In the formula (A-1), Me represents a methyl group.

In the present invention, the component (A) is preferably used in an amount within a range of 0.01 to 5 parts by mass, more preferably 0.03 to 1 part by mass, based on 100 parts by mass of trioxane.

(B) Cyclic Acetal Compound having oxyalkylene group of 2 or more carbon atoms in the Ring

In the present invention, (B) a cyclic acetal compound having an oxyalkylene group having 2 or more carbon atoms in the ring can also be used as a comonomer.

The cyclic acetal compound having an oxyalkylene group having 2 or more carbon atoms in the ring according to the present invention means: specific examples of the compound generally used as a comonomer in the production of the polyacetal copolymer include 1, 3-dioxolane, 1,3, 6-trioxane, 1, 4-butanediol formal, and the like.

In the present invention, the component (B) is preferably used in an amount within a range of 0.01 to 20 parts by mass, more preferably 0.05 to 5 parts by mass, based on 100 parts by mass of trioxane.

< method for producing polyacetal copolymer >

The method for producing a polyacetal copolymer of the present invention is characterized by copolymerizing trioxane and (A) a specific cyclic siloxane compound having 2 or more epoxy groups in the molecule, which is represented by the formula (1), in the presence of a cationic polymerization catalyst.

< cationic polymerization catalyst >

As the cationic polymerization catalyst, a polymerization catalyst known for cationic copolymerization using trioxane as a main monomer can be used. Typical examples thereof include protonic acids and Lewis acids.

Proton acid

Examples of the protonic acid include perfluoroalkanesulfonic acid, heteropolyacid, and isopoly acid.

Specific examples of perfluoroalkanesulfonic acids include trifluoromethanesulfonic acid, pentafluoroethanesulfonic acid, heptafluoropropanesulfonic acid, nonafluorobutanesulfonic acid, undecafluoropentanesulfonic acid, tridecafluorohexanesulfonic acid, pentadecafluoroheptanesulfonic acid, and heptadecafluorooctanesulfonic acid.

The heteropoly acid is a polyacid produced by dehydration condensation of various kinds of oxo acids, and has a single-core or multi-core complex ion in which a specific different element is present in the center and an oxygen atom is shared to enable condensation of a condensed acid group. Isopoly acids, also known as isopoly acids, homonuclear condensation acids, isopoly acids, refer to high molecular weight inorganic oxoacids formed from the condensation of inorganic oxoacids of a single type of metal having a valence of V or VI.

Specific examples of the heteropoly-acid include phosphomolybdic acid, phosphotungstic acid, phosphomolybdotungstic acid, phosphomolybdovanadic acid, phosphomolybdotungstovanadic acid, phosphotungstovanadic acid, silicotungstic acid, silicomolybdic acid, silicomolybdotungstic acid, silicomolybdotungstovanadic acid, and the like. In particular, from the viewpoint of polymerization activity, the heteropoly-acid is preferably selected from the group consisting of silicomolybdic acid, silicotungstic acid, phosphomolybdic acid, and phosphotungstic acid.

Specific examples of the isopoly acid include tungsten isopoly acids exemplified by paratungstic acid, metatungstic acid, and the like; molybdenum isopolyacids exemplified by paramolybdic acid, metamolybdic acid, and the like; metavanadate, vanadium isopoly acid, and the like. Among them, tungsten isopoly acid is preferable from the viewpoint of polymerization activity.

Lewis acid

Examples of the lewis acid include halides of boron, tin, titanium, phosphorus, arsenic and antimony, and specifically, boron trifluoride (and its ether complex), tin tetrachloride, titanium tetrachloride, phosphorus pentafluoride, phosphorus pentachloride, antimony pentafluoride, and complexes or salts thereof.

The amount of the polymerization catalyst is not particularly limited, but is preferably 0.1ppm to 50ppm, more preferably 0.1ppm to 30ppm, based on the total amount of all monomers.

In the production of the polyacetal copolymer of the present invention, in addition to the above-mentioned components, a component for adjusting the molecular weight may be used in combination to adjust the amount of the terminal group. Examples of the component for adjusting the molecular weight include compounds having an alkoxy group such as methylal, monomethoxymethylal, dimethoxymethylal, which are chain transfer agents not forming an unstable terminal.

The method for producing the polyacetal copolymer of the present invention is not particularly limited. The polymerization apparatus is not particularly limited during the production, and any known apparatus, such as a batch type or a continuous type, may be used. Further, the polymerization temperature is preferably maintained at 65 ℃ or higher and 135 ℃ or lower.

The cationic polymerization catalyst is preferably used by diluting with an inactive solvent which does not adversely affect the polymerization.

The deactivation of the polymerization catalyst after the polymerization can be carried out by a conventionally known method. For example, the polymerization may be carried out by adding a basic compound or an aqueous solution thereof to the reaction product discharged from the polymerization reactor or the reaction product in the polymerization reactor after the polymerization reaction.

The basic compound used for neutralizing and deactivating the polymerization catalyst is not particularly limited. After polymerization and deactivation, washing, separation and recovery of unreacted monomers, drying, and the like are further performed by a conventionally known method as needed.

The polyacetal copolymer obtained as described above preferably has a weight average molecular weight corresponding to methyl methacrylate determined by size exclusion chromatography of 10000 to 500000, particularly 20000 to 150000. In addition, for the terminal groups, from¹Hemiacetaldehyde powder detected by H-NMRThe amount of the terminal groups (for example, according to the method described in Japanese patent application laid-open No. 2001-11143) is preferably 0 to 4mmol/kg, and particularly preferably 0 to 2 mmol/kg.

In order to control the hemiformal end group content within the above range, impurities, particularly water, in the total amount of monomers and comonomers to be polymerized are preferably 20ppm or less, and particularly preferably 10ppm or less.

The polyacetal copolymer of the present invention is preferably blended with various known stabilizers selected as necessary. The stabilizer used here may be any one of 1 or 2 or more of hindered phenol compounds, nitrogen-containing compounds, hydroxides, inorganic salts, and carboxylates of alkali metals or alkaline earth metals.

Further, to the polyacetal copolymer of the present invention, 1 or 2 or more kinds of additives commonly used for thermoplastic resins, for example, coloring agents such as dyes and pigments, lubricants, nucleating agents, mold release agents, antistatic agents, surfactants, or organic polymer materials, inorganic or organic fibrous, powdery, and plate-like fillers, may be added as necessary.

Examples

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

< polymerization >

300g of trioxane was charged into a closed autoclave having a jacket through which a heat medium can flow and stirring blades, and further, the compound shown in Table 1 as the component (A) and, in some cases, 1, 3-Dioxolane (DO) as the component (B) were added in proportions each representing 1 part by mass. The contents were stirred, hot water at 80 ℃ was passed through the jacket, and after maintaining the internal temperature at about 80 ℃, a catalyst solution (phosphotungstic acid (PWA) as a solution of methyl formate, boron trifluoride dibutyl ether complex (BF) was added₃OBu₂) Dibutyl ether solution) was adjusted to the catalyst concentration (with respect to the whole monomer) shown in table 1 to initiate polymerization. When boron trifluoride dibutyl ether complex is used, the catalyst concentration is expressed as the concentration of boron trifluoride.

The component (A) used in the examples was the following (A-1).

After 5 minutes, 300g of water containing 0.1% triethylamine was added to the autoclave, the reaction was stopped, the contents were taken out, pulverized to 200 mesh or less, washed with acetone and dried, and then the yield of the polyacetal copolymer (the ratio (%) to the copolymer obtained by adding all the monomers) was calculated. The results are shown in table 1.

For comparison, the following diglycidyl compounds (X-1 and X-2) were used in the polymerization instead of the component (A-1) of the present invention to obtain a comparative polyacetal copolymer.

X-1: butanediol diglycidyl ether

X-2: trimethylolpropane triglycidyl ether

To 100 parts by mass of the polyacetal copolymer obtained in the above-mentioned manner, 0.35 part by mass of pentaerythritol-tetrakis [ 3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ] and 0.15 part by mass of melamine were added as stabilizers, and the mixture was melt-kneaded at 210 ℃ in a small twin-screw extruder to obtain a polyacetal resin composition in the form of pellets.

The pellets were used for the following evaluations. The results are shown in Table 2.

< tensile Strength >

The tensile strength of the ISOType1A test piece was measured in accordance with ISO527-1, 2. The measuring chamber was kept in an atmosphere of 50% RH at 23 ℃.

< flexural Strength and flexural modulus >

The flexural strength and flexural modulus were determined in accordance with ISO 178. The measuring chamber was kept in an atmosphere of 50% RH at 23 ℃.

[ Table 1]

[ Table 2]

In examples 1 to 8, it is clear that a polyacetal copolymer was obtained in a high yield with a low amount of catalyst, and that the polyacetal copolymer was excellent in mechanical properties. In comparative examples 5 and 6, no polymerization was observed at the same catalyst amount. In comparative examples 5 and 6, when the amount of the catalyst was set to 20ppm, a sudden and rapid reaction occurred, but the final yield was as low as about 50%.

As is clear from the results of tables 1 and 2, the present invention provides a novel polyacetal copolymer excellent in production stability and mechanical properties, and a method for producing the same.