阅读说明：本技术 层叠体的制造方法 (Method for producing laminate ) 是由 早坂健太郎 赤羽彻也 牧野邦彦 于 2018-07-24 设计创作，主要内容包括：本发明提供一种层叠体的制造方法,上述层叠体具有基材和橡胶层,上述橡胶层自上述基材表面起的厚度为200μm以上,上述制造方法通过使上述基材以加热状态与25℃时的粘度为2000～100000mPa·s的聚合物胶乳接触来使接触的上述聚合物凝固,由此形成上述橡胶层。(The present invention provides a method for producing a laminate comprising a base material and a rubber layer, wherein the rubber layer has a thickness of 200 [ mu ] m or more from the surface of the base material, wherein the base material is brought into contact with a polymer latex having a viscosity of 2000 to 100000 mPas at 25 ℃ in a heated state, and the polymer thus brought into contact is coagulated to form the rubber layer.)

1. A method for producing a laminate comprising a base material and a rubber layer, wherein the rubber layer has a thickness of 200 [ mu ] m or more from the surface of the base material,

the method comprises bringing the base material into contact with a polymer latex having a viscosity of 2000 to 100000 mPas at 25 ℃ in a heated state to coagulate the polymer latex in contact with the base material, thereby forming the rubber layer.

2. The method for producing a laminate according to claim 1, wherein the substrate is brought into contact with the polymer latex in a state heated to 30 ℃ or higher.

3. The method for producing a laminate according to claim 1 or 2, wherein the substrate is brought into contact with the polymer latex in a state heated to 50 ℃ or higher.

4. The method for producing a laminate according to any one of claims 1 to 3, wherein the thickness of the base material is 0.01 to 3000mm, and the thickness of the rubber layer penetrating into the base material is 1 μm or more and less than the thickness of the base material.

5. The method for producing a laminate according to any one of claims 1 to 4, wherein the polymer constituting the polymer latex is a nitrile rubber.

6. The method for producing a laminate according to any one of claims 1 to 5, wherein the polymer latex contains a nonionic surfactant.

7. A method for producing a protective glove, using the laminate obtained by the production method according to any one of claims 1 to 6.

Technical Field

The present invention relates to a laminate having a base material and a rubber layer formed of a polymer latex. The present invention also relates to a method for producing a protective glove using the laminate.

Background

Conventionally, protective gloves have been used for various purposes such as factory production, light-weight work, construction work, agricultural work, and the like, in which solvent resistance, grip properties, abrasion resistance, and the like are improved by covering gloves made of fibers with rubber, resin, or the like.

Such protective gloves are generally in contact with the human body during use, and therefore are required to have excellent mechanical strength such as abrasion resistance and durability, and also to have excellent flexibility.

For example, patent document 1 discloses a method for manufacturing a protective glove in which a fibrous glove is dipped in a coagulant solution, and then the fibrous glove dipped in the coagulant solution is dipped in a latex composition containing a nitrile rubber latex to form a surface rubber layer.

Disclosure of Invention

Problems to be solved by the invention

On the other hand, in the protective gloves, from the viewpoint of improving the protective property against a solvent, it is desired to increase the thickness of the surface rubber layer formed on the surface of the glove made of fibers. In contrast, in the method using a coagulant solution as in the production method of patent document 1, in order to increase the thickness of the surface rubber layer formed on the surface of the protective glove, it is necessary to immerse the fiber glove as the base material in the latex composition a plurality of times. However, when such a method is used, there is a problem that the number of production steps increases, and there is also a problem that: since the obtained surface rubber layer is formed by a plurality of times of dip molding, an interface is formed in the surface rubber layer, and such an interface causes easy peeling, and therefore, wearing durability is poor. Further, a method of thickening the thickness of the surface rubber layer by using a latex composition having a relatively high viscosity as the latex composition for dip molding is also considered. However, when such a method is used, there are the following problems: in the formation of the surface rubber layer, solidification proceeds unevenly, whereby cracks are generated in the formation of the surface rubber layer, and wear durability is poor due to such cracks.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method for producing a laminate which is less likely to cause peeling and cracking of a surface rubber layer, has high solvent resistance, and is excellent in wearability, flexibility, and abrasion resistance. Another object of the present invention is to provide a method for producing a protective glove using the laminate obtained by the above production method.

Means for solving the problems

As a result of intensive studies to achieve the above object, the present inventors have found that a rubber layer having a thickness of 200 μm or more from the surface of a base material can be formed on the surface of the base material by bringing a heated base material into contact with a polymer latex having a viscosity of 2000 to 100000mPa · s at 25 ℃ to coagulate the polymer latex in contact, and that a laminate in which the rubber layer is formed on the base material can effectively prevent the occurrence of peeling and cracking of the surface rubber layer, has high solvent resistance, and is excellent in wearability, flexibility and abrasion resistance, and have completed the present invention.

That is, according to the present invention, there is provided a method for producing a laminate having a base material and a rubber layer, wherein the rubber layer has a thickness of 200 μm or more from the surface of the base material, the method comprising bringing the base material into contact with a polymer latex having a viscosity of 2000 to 100000mPa · s at 25 ℃ in a heated state, and coagulating the polymer latex in contact therewith to form the rubber layer.

In the production method of the present invention, the base material is preferably brought into contact with the polymer latex in a state of being heated to 30 ℃ or higher.

In the production method of the present invention, the base material is preferably brought into contact with the polymer latex in a state heated to 50 ℃ or higher.

In the production method of the present invention, the thickness of the base material is preferably 0.01 to 3000mm, and the thickness of the rubber layer penetrating into the base material is preferably 1 μm or more and less than the thickness of the base material.

In the production method of the present invention, it is preferable that the polymer constituting the polymer latex is a nitrile rubber.

In the production method of the present invention, the polymer latex preferably contains a nonionic surfactant.

Further, the present invention can provide a method for producing a protective glove using the laminate obtained by the above-described production method.

Effects of the invention

The present invention can provide a method for producing a laminate which is less likely to cause peeling and cracking of the surface rubber layer, has high solvent resistance, and is excellent in wearability, flexibility, and abrasion resistance. Further, according to the present invention, a method for producing a protective glove using the laminate obtained by the production method can be provided.

Drawings

Fig. 1(a) is a sectional view of a fiber base material before a rubber layer is formed, and fig. 1(B) is a sectional view of a laminate in which a rubber layer is laminated on the fiber base material shown in fig. 1 (a).

Detailed Description

The method for producing a laminate of the present invention is a method for producing a laminate comprising a base material and a rubber layer, wherein the rubber layer has a thickness of 200 μm or more from the surface of the base material,

the rubber layer is formed by bringing the base material into contact with a polymer latex having a viscosity of 2000 to 100000 mPas at 25 ℃ in a heated state and coagulating the polymer latex in contact with the base material.

The laminate obtained by the production method of the present invention has a base material and a rubber layer having a thickness of 200 μm or more from the surface of the base material. The laminate obtained by the production method of the present invention can be used for applications requiring flexibility, and is not particularly limited, and for example, a fiber base material is preferably used as a base material, and a laminate having a fiber base material and a rubber layer is preferably used, and particularly preferably used as a material used in contact with a human body, such as a glove for operation, particularly a protective glove for home use, agricultural use, fishery use, industrial use, and the like.

The fiber base material is not particularly limited as long as it is a base material made of fibers, and natural fibers such as cotton, wool, hemp and wool, synthetic fibers such as polyester, polyurethane, acrylic and nylon, and the like can be used as a material. The fiber base material may be a woven base material, a sewn base material, a woven fabric, or a nonwoven fabric.

The thickness of the fiber base material (the average thickness d of the base material layer of the fiber base material described later) is not particularly limited, but is preferably 0.01 to 3.00mm, more preferably 0.02 to 2.00mm, and further preferably 0.03 to 1.5 mm. The linear density of the fiber base material is not particularly limited, and is preferably 50 to 500 deniers. The number of needles of the fiber base material is not particularly limited, but is preferably 7 to 18 needles. Here, the needle count refers to the number of needles of the knitting machine between 1 inch.

In the production method of the present invention, a base material is brought into contact with a polymer latex having a viscosity of 2000 to 100000 mPas at 25 ℃ while being heated, and the contacted polymer latex is coagulated by the heat of the base material, that is, a rubber layer is formed by a heat-sensitive coagulation method (heat-sensitive dipping method), thereby producing a laminate having the base material and the rubber layer having a thickness of 200 μm or more from the surface of the base material.

Specifically, in the case of producing a laminate, a base material is immersed in a polymer latex in a heated state to adhere the polymer latex to the surface of the base material, and the polymer latex adhered to the surface of the base material is brought into contact with the heated base material to gelate and coagulate the polymer latex adhered to the surface of the base material, thereby forming a rubber layer. In the case where the base material is immersed in the polymer latex in a heated state, the base material may be immersed in a state in which the base material covers a mold corresponding to the shape of the base material. For example, in the case where the laminate is a protective glove, when the glove-shaped fiber base material is immersed in the polymer latex in a heated state, the glove-shaped fiber base material may be immersed in a state in which it covers the glove mold.

In particular, according to such a thermosensitive coagulation method, the polymer latex can be attached to the surface of the base material by dipping the heated base material in the polymer latex, and the polymer latex attached to the surface of the base material can be appropriately gelled and coagulated with relatively high uniformity by the action of heat of the base material. Therefore, according to the production method of the present invention, even when a relatively high viscosity latex having a viscosity of 2000 to 100000mPa · s at 25 ℃ is used as the polymer latex, thereby making the thickness of the polymer latex adhered to the surface of the substrate thick, gelation and coagulation of the polymer latex can be appropriately performed with relatively high uniformity. In addition, even when the thickness of the rubber layer formed on the base material is relatively large, i.e., 200 μm or more from the surface of the base material, the occurrence of peeling and cracks can be effectively prevented, and as a result, the obtained laminate can have high solvent resistance and excellent wearability, flexibility, and abrasion resistance.

In the case where a fibrous base material or the like is used as the base material, for example, when the laminate is a protective glove, when the heated base material is immersed in the polymer latex, it is preferable that a part of the polymer latex is immersed in the base material, whereby the thickness of the formed rubber layer from the surface of the base material is 200 μm or more and a part thereof can penetrate into the base material. This can provide a laminate having excellent abrasion resistance and excellent solvent resistance.

Here, an embodiment of a laminate obtained by the production method of the present invention, that is, a laminate having a fiber base material and a rubber layer will be described with reference to fig. 1(a) and 1 (B). Fig. 1(a) is a cross-sectional view of the fiber base material before the rubber layer is formed, and fig. 1(B) is a cross-sectional view of a laminate in which the rubber layer is laminated on the fiber base material shown in fig. 1 (a). Fig. 1(B) shows an example in which the rubber layer is formed so as to cover the fiber base material in a state in which a part of the rubber layer penetrates between fibers constituting the fiber base material. In fig. 1(B), the rubber layer constituting the laminate is illustrated as a penetrated rubber layer in which a portion penetrating from the surface of the fiber base material to the fiber gap is present, and the rubber layer is illustrated as a surface rubber layer in which a portion covering the fiber base material from the surface of the fiber base material is present. In the present invention, the rubber layer is appropriately described as a layer composed of a permeable rubber layer and a surface rubber layer, but usually these permeable rubber layer and surface rubber layer are integrally formed. Hereinafter, description will be given with reference to fig. 1(a) and 1(B) as appropriate.

In the laminate obtained by the production method of the present invention, the thickness of the rubber layer formed on the base material from the surface of the base material (the thickness t of the surface rubber layer shown in fig. 1 (B))₁) Is 200 μm or more, preferably 200 to 5000 μm, more preferably 200 to 3000 μm, further preferably 200 to 2000 μm, and particularly preferably 210 to 2000 μm, from the viewpoint of further suitably improving the protective property against a solvent. When the thickness of the rubber layer formed on the base material from the surface of the base material (thickness t of the surface rubber layer)₁) If the thickness is less than 200 μm, the resulting laminate is poor in solvent repellency, and is not suitable for applications requiring solvent repellency, for example, protective glove applications requiring solvent repellency.

In addition, in the laminate obtained by the production method of the present invention, the thickness of the portion of the rubber layer formed on the base material, which penetrates into the base material (the thickness t of the penetrated rubber layer shown in fig. 1 (B)) (thickness t of the penetrated rubber layer)₂) Preferably 1 μm or more, more preferably 5 μm or more, and further preferably 10 μm or more. By makingThe thickness of the portion penetrating into the base material (thickness t of the penetrating rubber layer shown in FIG. 1B)₂) In the above range, the effect of forming a portion (a permeable rubber layer shown in fig. 1B) penetrating into the base material, that is, the effect of improving the wear resistance and the effect of improving the solvent repellency can be further improved. The thickness of the rubber layer formed on the base material at the portion penetrating into the base material (thickness t of the penetrated rubber layer shown in fig. 1 (B)) is₂) The upper limit of (B) is not particularly limited, but is preferably smaller than the thickness of the base material (the average thickness d of the base material layer of the fiber base material shown in fig. 1 (B)) from the viewpoint of preventing the rubber layer from reaching the back surface of the base material and penetrating therethrough, and is more preferably 3000 μm or less, and even more preferably 2000 μm or less from the viewpoint of flexibility. Further, when the rubber layer penetrates through the back surface of the base material, the wearability may be lowered, and the productivity of the laminate may be lowered (for example, in the case where the base material is attached to a predetermined mold and the polymer latex is adhered to the base material to form the rubber layer, the polymer latex is adhered to the mold due to the penetration, and the resulting laminate is less likely to be detached from the mold, and the productivity is lowered).

Further, from the viewpoint of highly balancing wearability, flexibility, and abrasion resistance, the thickness of the portion of the rubber layer formed on the base material penetrating into the base material (the thickness t of the penetrated rubber layer shown in fig. 1 (B)) is set to be equal to the thickness of the rubber layer formed on the base material₂) The thickness of the rubber layer formed on the base material from the surface of the base material (the thickness t of the surface rubber layer shown in FIG. 1B)₁) Ratio (t)₂/t₁) Preferably 0.001 to 15, more preferably 0.005 to 10, and further preferably 0.01 to 5.

Further, from the viewpoint of highly balancing the wearability, flexibility and abrasion resistance of the laminate obtained by the production method of the present invention, the thickness of the rubber layer formed on the base material from the surface of the base material (the thickness t of the surface rubber layer shown in fig. 1 (B)) is₁) The ratio (t) of the thickness of the base material (average thickness d of the base material layer of the fiber base material shown in FIG. 1B) to the thickness of the base material₁The amount of the compound,/d) is preferably 0.1 to 300, more preferably 0.15 to 30, and still more preferably 0.2 to 15.Further, the total thickness of the laminate (thickness t of the surface rubber layer shown in FIG. 1B)₁And the average thickness d of the base material layer of the fiber base material) is preferably 0.2 to 8mm, more preferably 0.2 to 4.5 mm. In addition, since the fiber base material may have a different thickness in its microstructure because there are a portion where the degree of overlapping of the fibers is dense and a portion where the degree of overlapping of the fibers is sparse, the average thickness d of the base material layer of the fiber base material shown in fig. 1(B) is determined as follows: the average thickness of the portions where the degree of overlapping of the fibers is dense was obtained for the fiber base material, and this was taken as the thickness of the fiber base material.

The polymer constituting the polymer latex used in the production method of the present invention is not particularly limited in kind, and examples thereof include: natural rubber; conjugated diene rubbers obtained by polymerizing or copolymerizing conjugated dienes such as butadiene and isoprene. Among these, conjugated diene rubbers are preferable. Examples of the conjugated diene rubber include so-called nitrile rubbers obtained by copolymerizing nitrile group-containing monomers, isoprene rubbers, styrene-butadiene rubbers, chloroprene rubbers, and the like, and among these, nitrile rubbers are particularly preferable.

The nitrile rubber is not particularly limited, and a rubber obtained by copolymerizing α -ethylenically unsaturated nitrile monomer and, if necessary, another copolymerizable monomer can be used.

The α -ethylenically unsaturated nitrile monomer is not particularly limited, and an ethylenically unsaturated compound having a nitrile group and preferably 3 to 18 carbon atoms can be used, and examples of the α -ethylenically unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, halogen-substituted acrylonitrile, and the like, and among these, acrylonitrile is particularly preferred, and 1 kind of these α -ethylenically unsaturated nitrile monomers can be used alone, or 2 or more kinds can be used in combination.

The nitrile rubber preferably contains α -ethylenically unsaturated nitrile monomer units in an amount of 10 to 45 wt%, more preferably 20 to 40 wt%, and even more preferably 30 to 40 wt% based on the total monomer units, and the α -ethylenically unsaturated nitrile monomer unit content is in the above range, whereby the solvent resistance of the resulting laminate can be improved, and furthermore, the α -ethylenically unsaturated nitrile monomer unit content is in the above range, whereby when a rubber layer is formed by a thermal coagulation method using a polymer latex containing such a nitrile rubber, the nitrile rubber can be gelled and coagulated more favorably, and the rubber layer can be formed more favorably, whereby when the resulting laminate is used as a protective glove or the like to be worn on a hand, the feeling of discomfort of the hand can be further reduced, and the comfort during wearing can be further improved.

In addition, as the nitrile rubber, from the viewpoint of imparting rubber elasticity, a nitrile rubber containing a conjugated diene monomer unit is preferable. The conjugated diene monomer forming the conjugated diene monomer unit is preferably a conjugated diene monomer having 4 to 6 carbon atoms such as 1, 3-butadiene, isoprene, 2, 3-dimethyl-1, 3-butadiene, 1, 3-pentadiene, chloroprene, etc., more preferably 1, 3-butadiene and isoprene, and particularly preferably 1, 3-butadiene. These conjugated diene monomers may be used alone in 1 kind, or 2 or more kinds may be used in combination.

The content ratio of the conjugated diene monomer unit is preferably 40 to 80% by weight, more preferably 52 to 78% by weight, based on the total monomer units constituting the nitrile rubber. By setting the content ratio of the conjugated diene monomer unit to the above range, the flexibility of the laminate obtained can be further improved.

In addition, the nitrile rubber may also contain other ethylenically unsaturated acid monomers capable of copolymerizing with the α -ethylenically unsaturated nitrile monomer unit-forming monomers and the conjugated diene monomer unit-forming monomers.

The other copolymerizable ethylenically unsaturated acid monomer is not particularly limited, and examples thereof include a carboxyl group-containing ethylenically unsaturated monomer, a sulfonic acid group-containing ethylenically unsaturated monomer, and a phosphoric acid group-containing ethylenically unsaturated monomer.

The carboxyl group-containing ethylenically unsaturated monomer is not particularly limited, and examples thereof include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; ethylenically unsaturated polycarboxylic acids such as fumaric acid, maleic acid, itaconic acid, maleic anhydride, and itaconic anhydride, and anhydrides thereof; and partial ester compounds of ethylenically unsaturated polycarboxylic acids such as methyl maleate and methyl itaconate.

The sulfonic acid group-containing ethylenically unsaturated monomer is not particularly limited, and examples thereof include vinylsulfonic acid, methylvinylsulfonic acid, styrenesulfonic acid, (meth) allylsulfonic acid, (meth) acrylic acid-2-sulfonic acid ethyl ester, and 2-acrylamido-2-hydroxypropanesulfonic acid.

The ethylenically unsaturated monomer containing a phosphoric acid group is not particularly limited, and examples thereof include 3-chloro-2-propyl (meth) acrylate, 2-ethyl (meth) acrylate, and 3-allyloxy-2-hydroxypropane phosphoric acid.

These copolymerizable other ethylenically unsaturated acid monomers may be used as alkali metal salts or ammonium salts, and 1 kind thereof may be used alone or 2 or more kinds thereof may be used in combination. Among the above-mentioned other ethylenically unsaturated acid monomers copolymerizable therewith, carboxyl group-containing ethylenically unsaturated monomers are preferable, ethylenically unsaturated monocarboxylic acids are more preferable, and methacrylic acid is particularly preferable.

The polymer latex can be obtained by, for example, emulsion polymerization of a monomer mixture containing the above-mentioned monomer. In the emulsion polymerization, a polymerization auxiliary material such as an emulsifier, a polymerization initiator, and a molecular weight regulator, which are generally used, can be used.

The emulsifier used in the emulsion polymerization is not particularly limited, and examples thereof include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and the like, and nonionic surfactants are preferable from the viewpoint of more suitably proceeding the thermosensitive coagulation. In particular, in the case of the coagulation immersion method using a coagulant solution containing a coagulant such as calcium nitrate, an anionic surfactant is preferably used as an emulsifier for emulsion polymerization from the viewpoint of efficiently performing salt coagulation, but in the present invention, a nonionic surfactant is preferably used from the viewpoint of more suitably performing thermosensitive coagulation, and a water-soluble nonionic polymer having a cloud point of not less than room temperature and not more than 100 ℃. Specific examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, and polyoxyethylene sorbitan alkyl esters.

The amount of the emulsifier used for emulsion polymerization is preferably 0.5 to 10 parts by weight, more preferably 1 to 8 parts by weight, based on 100 parts by weight of the total monomers used.

The polymerization initiator is not particularly limited, and a radical initiator is preferable. The radical initiator is not particularly limited, and examples thereof include: inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide; organic peroxides such as t-butyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, dibenzoyl peroxide, 3,5, 5-trimethylhexanoyl peroxide, and t-butyl peroxyisobutyrate; azo compounds such as azobisisobutyronitrile, azobis-2, 4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, and azobismethyl isobutyrate, among which inorganic peroxides and organic peroxides are preferred, inorganic peroxides are more preferred, and persulfates are particularly preferred. These polymerization initiators may be used alone in 1 kind, or 2 or more kinds may be used in combination.

The amount of the polymerization initiator used is preferably 0.01 to 2 parts by weight, more preferably 0.05 to 1.5 parts by weight, based on 100 parts by weight of the total monomers used.

The molecular weight modifier is not particularly limited, and examples thereof include α -methylstyrene dimer, mercaptans such as t-dodecylmercaptan, n-dodecylmercaptan and octylmercaptan, halogenated hydrocarbons such as carbon tetrachloride, methylene chloride and methylene bromide, sulfur-containing compounds such as tetraethylthiuram disulfide, dipentamethylenethiuram disulfide and diisopropyl xanthogen disulfide, among which mercaptans are preferable, and t-dodecylmercaptan is more preferable, and 1 kind or 2 or more kinds of these molecular weight modifiers may be used alone or in combination.

The amount of the molecular weight modifier used varies depending on the kind thereof, and is preferably 0.1 to 1.5 parts by weight, more preferably 0.2 to 1.0 part by weight, based on 100 parts by weight of the total monomers used.

Emulsion polymerization is generally carried out in water. The amount of water used is preferably 80 to 500 parts by weight, more preferably 100 to 200 parts by weight, based on 100 parts by weight of the total monomers used.

In the emulsion polymerization, a polymerization auxiliary material other than the above may be further used as necessary. Examples of the polymerization auxiliary material include a chelating agent, a dispersant, a pH adjuster, a deoxidizer, a particle size adjuster, and the like, and the kind and the amount of these are not particularly limited.

Examples of the method of adding the monomer include: a method of adding a monomer to be used in a reaction vessel at once; a method of continuously or intermittently adding the polymer as the polymerization proceeds; any method may be employed, for example, a method in which a part of the monomer is added to react to a specific conversion, and then the remaining monomer is continuously or intermittently added to polymerize the monomer. When the monomers are mixed and continuously or intermittently added, the composition of the mixture may be constant or may be changed.

The monomers may be added to the reaction vessel after being mixed in advance, or may be added to the reaction vessel separately.

The polymerization temperature in the emulsion polymerization is not particularly limited, but is usually 0 to 95 ℃ and preferably 5 to 70 ℃. The polymerization time is not particularly limited, but is usually about 5 to 40 hours.

The polymerization terminator is not particularly limited as long as it is a polymerization terminator generally used in emulsion polymerization, and specific examples thereof include: hydroxylamine compounds such as hydroxylamine, hydroxylamine sulfate, diethylhydroxylamine, hydroxylamine sulfonic acid and alkali metal salts thereof; sodium dimethyldithiocarbamate; a hydroquinone derivative; a catechol derivative; aromatic hydroxydithiocarboxylic acids such as hydroxydimethylthiophenecarboxylic acid, hydroxydiethylbenzenedithiocarboxylic acid and hydroxydibutylbenzenedithiocarboxylic acid, and aromatic hydroxydithiocarboxylic acid compounds such as alkali metal salts thereof.

The amount of the polymerization terminator to be used is not particularly limited, and is usually 0.05 to 2 parts by weight based on 100 parts by weight of the total monomers to be used.

After the termination of the polymerization reaction, the concentration of the solid content and the pH may be adjusted by removing unreacted monomers as desired.

The weight average particle diameter of the polymer particles constituting the polymer latex is usually 30 to 1000nm, preferably 50 to 500nm, and more preferably 70 to 200 nm. When the weight average particle diameter of the polymer particles is in the above range, the viscosity of the polymer latex becomes appropriate, the handling property of the polymer latex is further improved, and the moldability at the time of molding the rubber layer is improved, and a laminate having a more uniform rubber layer can be obtained.

The solid content concentration of the polymer latex is usually 20 to 65% by weight, preferably 30 to 60% by weight, and more preferably 35 to 55% by weight. When the solid content concentration of the polymer latex is in the above range, the latex conveying efficiency can be improved, the viscosity of the polymer latex can be adjusted appropriately, and the handling property of the polymer latex can be improved.

The pH of the polymer latex is usually 5 to 13, preferably 7 to 10, and more preferably 7.5 to 9. When the pH of the polymer latex is in the above range, the mechanical stability can be improved, generation of coarse aggregates during transportation of the polymer latex can be suppressed, the viscosity of the polymer latex can be adjusted appropriately, and the handling property of the polymer latex can be improved.

The polymer latex used in the production method of the present invention has a viscosity at 25 ℃ of 2000 to 100000 mPas, preferably 2500 to 50000 mPas, more preferably 3000 to 20000 mPas, still more preferably 4000 to 20000 mPas, and particularly preferably 5000 to 20000 mPas. By using a latex having a viscosity at 25 ℃ in the above range as the polymer latex, the rubber layer can be formed by a thermal coagulation method such that the thickness of the rubber layer formed on the base material from the surface of the base material is 200 μm or more, and even when the rubber layer is formed in such a thickness, the obtained laminate can be excellent in wearability, flexibility and abrasion resistance. The viscosity of the polymer latex at 25 ℃ can be measured, for example, using a B-type viscometer at 25 ℃ and at a rotation speed of 6 rpm. Further, as a method for adjusting the viscosity of the polymer latex at 25 ℃, for example, there can be mentioned: a method of adjusting the polymer concentration in the polymer latex; a method of adjusting a compound having a thickening effect to the polymer latex (in this case, it can be used as a latex composition), and the like.

As the polymer latex, a latex containing a compounding agent such as a crosslinking agent or a heat-sensitive coagulant is preferably used. That is, it is preferably used as a composition of latex. When the polymer latex is used as a latex composition as described above, a latex composition having a viscosity at 25 ℃ in a state of containing a compounding agent such as the above-mentioned crosslinking agent or thermal coagulant and a compounding agent such as the below-mentioned emulsifier or thickener in the range of 2000 to 100000 mPas is used.

The crosslinking agent is preferably a sulfur-based crosslinking agent. The sulfur-based crosslinking agent is not particularly limited, and examples thereof include: sulfur such as powdered sulfur, sublimed sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, and insoluble sulfur; sulfur-containing compounds such as sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, dibenzothiazyl disulfide, caprolactam disulfide, phosphorus-containing polysulfide, and polymer polysulfide; sulfur donating compounds such as tetramethylthiuram disulfide, selenium dimethyldithiocarbamate, and 2- (4' -morpholinodithio) benzothiazole. These crosslinking agents may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

When the crosslinking agent is blended in the polymer latex, the blending amount of the crosslinking agent is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, and still more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the polymer contained in the polymer latex.

When sulfur is used as the crosslinking agent, it is preferable to use a crosslinking accelerator (vulcanization accelerator) and zinc oxide together.

The crosslinking accelerator (vulcanization accelerator) is not particularly limited, and examples thereof include: dithiocarbamic acids such as diethyldithiocarbamic acid, dibutyldithiocarbamic acid, di-2-ethylhexyldithiocarbamic acid, dicyclohexyldithiocarbamic acid, diphenyldithiocarbamic acid, dibenzyldithiocarbamic acid, and zinc salts thereof; 2-mercaptobenzothiazole, 2-mercaptobenzothiazole zinc, 2-mercaptothiazoline, dibenzothiazyl disulfide, 2- (2, 4-dinitrophenylthio) benzothiazole, 2- (N, N-diethylthiocarbamoylthio) benzothiazole, 2- (2, 6-dimethyl-4-morpholinothio) benzothiazole, 2- (4' -morpholinodithio) benzothiazole, 4-morpholinyl-2-benzothiazolyl disulfide, 1, 3-bis (2-benzothiazolylmethylmercapto) urea and the like, among which zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, 2-mercaptobenzothiazole and 2-mercaptobenzothiazole zinc are preferable. These crosslinking accelerators may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The heat-sensitive coagulant is not particularly limited as long as it is a compound that exhibits an action of coagulating the polymer latex by heating, and examples thereof include: epoxy-modified silicone oil, alkyl aralkyl-modified silicone oil, amino-modified silicone oil, carboxyl-modified silicone oil, alcohol-based modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, and the like; polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, polymethylhydrosiloxane, and diorganopolysiloxane diol; fluoroalkyl ester polymers such as 1, 1-dihydroperfluorooctyl acrylate polymers and perfluoroalkyl ethyl acrylate-alkyl acrylate copolymers. By blending a heat-sensitive coagulant in the polymer latex, the heat-sensitive coagulation of the polymer latex can be more appropriately performed.

When the heat-sensitive coagulant is blended in the polymer latex, the blending amount of the heat-sensitive coagulant is preferably 0.1 to 10 parts by weight, more preferably 0.1 to 8 parts by weight, and still more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the polymer contained in the polymer latex. When the amount of the thermosensitive coagulant blended is within the above range, the thermosensitive coagulation of the polymer latex can be more appropriately performed. In the present invention, the thermosensitive coagulant has an action as a thickener for thickening the polymer latex in addition to an action of coagulating the polymer latex by heating. Therefore, from the viewpoint of adjusting the polymer latex to the predetermined viscosity, the compounding amount of the thermosensitive coagulant is preferably within the above range.

In addition, from the viewpoint of further improving the stability of the polymer latex, an emulsifier may be further blended in the polymer latex. As the emulsifier, a nonionic surfactant is preferable as in the case of emulsion polymerization, a water-soluble nonionic polymer having a cloud point of 30 ℃ or more and 100 ℃ or less is preferable, and a water-soluble nonionic polymer having a cloud point of 45 ℃ or more and 90 ℃ or less is more preferable.

When an emulsifier is further blended in the polymer latex, the content of the emulsifier blended in the polymer latex (including the content of the emulsifier used in the emulsion polymerization of the polymer latex) is preferably 20 to 0.01 wt%, more preferably 15 to 0.02 wt%, and still more preferably 10 to 0.05 wt%. When the content ratio of the emulsifier is within the above range, the stability of the polymer latex can be further improved, and when the rubber layer is formed by the thermal coagulation method, the formation of the rubber layer can be further appropriately performed.

In addition to the above-mentioned heat-sensitive coagulant, a thickener other than the heat-sensitive coagulant may be appropriately added to the polymer latex. Such a thickener is not particularly limited, and examples thereof include: vinyl compounds such as polyvinyl alcohol and polyvinyl pyrrolidone; cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose, and carboxymethyl cellulose salts; polycarboxylic acid-based acid compounds and sodium salts thereof; polyoxyethylene derivatives such as polyethylene glycol ethers.

In the method for producing the laminate of the present invention, as described above, the base material is brought into contact with the polymer latex in a heated state to adhere the polymer latex to the surface of the base material, and the polymer latex adhered to the surface of the base material is brought into contact with the heated base material to gel and coagulate the polymer latex adhered to the surface of the base material, thereby forming the rubber layer having a thickness of 200 μm or more from the surface of the base material. The method of bringing the base material into contact with the polymer latex is not particularly limited, and examples thereof include a method of immersing the base material in the polymer latex. When the base material is immersed in the polymer latex, the base material may be supported by a mold for immersion having a desired shape by mounting or the like and immersed in the polymer latex in this state. When a latex to which a crosslinking agent is added is used as the polymer latex, a latex that has been previously cured (also referred to as precured) may be used as the polymer latex.

The impregnation mold for the support base is not particularly limited, and various molds made of ceramics, glass, metal, plastic, or the like can be used. The shape of the impregnation die may be set to a desired shape in accordance with the shape of the final product. For example, when the laminate having the rubber layer is a protective glove, various kinds of impregnation molds for gloves such as an impregnation mold having a shape from a wrist to a fingertip are preferably used as the impregnation mold in which the fibrous base material serving as the base material is coated.

When the base material is brought into contact with the polymer latex, the base material is heated (also referred to as preheating) in advance, and the fibrous base material supported on the impregnation die is brought into contact with the polymer latex in a heated state. The temperature of the substrate (also referred to as a preheating temperature) at the time of contact with the polymer latex is preferably 30 to 100 ℃, more preferably 40 to 95 ℃, still more preferably 45 to 90 ℃, particularly preferably 50 to 90 ℃, and most preferably 55 to 90 ℃. By setting the preheating temperature of the base material to the above range, the temperature of the base material immediately before contact with the polymer latex can be set to the following preferable range. The temperature of the base material immediately before contact with the polymer latex is preferably 25 to 100 ℃, more preferably 35 to 95 ℃, even more preferably 40 to 90 ℃, particularly preferably 45 to 90 ℃, and most preferably 50 to 90 ℃. When the temperature of the base material is in the above range, the rubber layer can be more appropriately formed when the rubber layer is formed by the thermal coagulation method using the polymer latex.

Further, it is preferable that the polymer latex adhered to the substrate is dried after the substrate is contacted with the polymer latex. The drying temperature in this case is not particularly limited, but is preferably 10 to 80 ℃ and more preferably 15 to 80 ℃. The drying time is also not particularly limited, but is preferably 5 seconds to 120 minutes, and more preferably 10 seconds to 60 minutes.

When a crosslinking agent is blended in the polymer latex, the polymer latex may be crosslinked by heating as necessary.

Further, when the rubber layer is formed in a state in which the base material is supported by the impregnation die, the base material on which the rubber layer is formed can be detached from the impregnation die to obtain a laminate. As the release method, a method of peeling off the resin from the impregnation mold by hand or a method of peeling off the resin by water pressure or pressure of compressed air can be used.