WO2019022092A1

WO2019022092A1 - Laminate production method

Info

Publication number: WO2019022092A1
Application number: PCT/JP2018/027768
Authority: WO
Inventors: 健太郎早坂; 赤羽　徹也; 邦彦牧野
Original assignee: 日本ゼオン株式会社
Priority date: 2017-07-27
Filing date: 2018-07-24
Publication date: 2019-01-31
Also published as: JP7163919B2; JPWO2019022092A1

Abstract

Provided is a production method for a laminate having a base material and a rubber layer formed penetrating from one surface to the other surface of the base material, the laminate production method involving a solidification step in which the rubber layer is formed by bringing the base material, which is supported on a dipping mold, into contact in a heated state with a polymer latex, whereby the polymer forming the polymer latex is caused to permeate the base material and the permeating polymer is solidified.

Description

Method of manufacturing laminate

The present invention relates to a laminate comprising a substrate and a rubber layer formed from a polymer latex. The present invention also relates to a method for producing a protective glove using the above laminate.

Conventionally, in various applications such as factory manufacturing work, light work, construction work, agricultural work, etc., the fiber gloves are coated with rubber, resin or the like to improve the solvent resistance, grip property, abrasion resistance etc. Protective gloves are used.

Since such protective gloves are usually used in contact with the human body, in addition to being excellent in mechanical strength and durability such as abrasion resistance, they are also required to be excellent in flexibility. It is done.

For example, Patent Document 1 discloses a protective glove formed by impregnating a fibrous glove with a coagulant solution and then bringing a latex composition containing nitrile rubber into contact to form a rubber layer. However, in the case of the protective glove obtained by the technique of Patent Document 1, when the rubber layer is formed so as to penetrate from the front surface to the back surface of the fiber glove, when the protective glove is actually worn in the hand, the rubber penetrated to the back surface When the layers come into contact with the hand, the hand feels unpleasant to the hand, and there is a problem that the comfort upon wearing is inferior.

International Publication No. 2017/014029

The present invention has been made in view of such a situation, and provides a method of manufacturing a laminate excellent in flexibility and wear resistance, moreover, hardly feeling fatigue at the time of wearing, and excellent in comfort at the time of wearing The purpose is to Another object of the present invention is to provide a method of producing a protective glove using the laminate obtained by such a production method.

The inventors of the present invention conducted intensive studies to achieve the above object, and as a result, a polymer latex was obtained by bringing the substrate supported on the immersion mold into contact with the polymer latex in a heated state. It is found that the above object can be achieved by forming a rubber layer penetrating from one surface of the substrate to the other surface by infiltrating the polymer constituting the into the substrate and coagulating the infiltrated polymer. The present invention has been completed.

That is, according to the present invention, there is provided a method of manufacturing a laminate comprising a base material and a rubber layer formed to penetrate from one surface of the base material to the other surface, which is formed on an immersion mold. By bringing the supported base material into contact with a polymer latex in a heated state, the polymer constituting the polymer latex is allowed to permeate the base material, and the permeated polymer is solidified. There is provided a method of manufacturing a laminate, comprising the step of solidifying the rubber layer.

In the method for manufacturing a laminate of the present invention, in the coagulation step, the polymer latex is preferably brought into contact in a state where the base material supported on the immersion mold is heated to 30 ° C. or higher.
In the method for producing a laminate of the present invention, it is more preferable that the polymer latex is brought into contact in a state where the substrate supported on the immersion mold is heated to 45 ° C. or more in the coagulation step.
In the method of producing a laminate of the present invention, the polymer constituting the polymer latex is preferably a nitrile rubber.
In the method for producing a laminate of the present invention, the polymer latex preferably contains a nonionic surfactant.

Moreover, according to this invention, the manufacturing method of a protective glove using the laminated body obtained by said manufacturing method is provided.

According to the present invention, it is possible to provide a method for producing a laminate which is excellent in flexibility and wear resistance, is not easily felt when worn, and is also excellent in wearing comfort. Furthermore, according to the present invention, it is possible to provide a method for producing a protective glove using the laminate obtained by such a production method.

FIG. 1 (A) is a cross-sectional view of the fiber base before forming the rubber layer, and FIG. 1 (B) is a protective glove formed by laminating the rubber layer on the fiber base shown in FIG. 1 (A). FIG.

The method for producing a laminate of the present invention is a method for producing a laminate comprising a substrate and a rubber layer formed to penetrate from one surface of the substrate to the other surface,
The polymer which has penetrated the polymer which constitutes the polymer latex into the substrate by making the polymer latex come into contact by bringing the substrate supported on the immersion mold into contact with the polymer latex in a heated state, the polymer And coagulating the rubber layer to form a rubber layer.

The laminate of the present invention comprises a substrate and a rubber layer. The laminate of the present invention can be used for applications requiring flexibility, and is not particularly limited. For example, as a laminate comprising a fiber substrate and a rubber layer, using a fiber substrate as the substrate It is preferable to use it, and it is particularly preferable to use as working gloves, especially protective gloves for household use, agriculture use, fishery use and industrial use, etc. in contact with human bodies.
In the following, with reference to FIG. 1 (A) and FIG. 1 (B), a protective glove having a fiber base and a rubber layer will be illustrated and described as an embodiment of the laminate of the present invention. 1 (A) is a cross-sectional view of the fiber base before forming the rubber layer, and FIG. 1 (B) is a polymer latex relative to the fiber base shown in FIG. 1 (A). It is a cross-sectional view of a protective glove provided with a rubber layer formed by infiltration and solidification.

The fiber base material may be made of fiber, and is not particularly limited, but natural fibers such as cotton, hair, hemp and wool, synthetic fibers such as polyester, polyurethane, acrylic and nylon may be used as the material Among these, it is preferable to use nylon. In addition, the fiber base material may be knitted or sewn, and may be woven or non-woven.

The thickness of the fiber substrate (average thickness d of the substrate layer of the fiber substrate described later) is not particularly limited, but preferably 0.05 to 3.00 mm, more preferably 0.10 to 2.00 mm, and still more preferably It is 0.15 to 1.5 mm. The linear density of the fiber substrate is not particularly limited, but preferably 50 to 500 denier. The gauge number of the fiber substrate is not particularly limited, but is preferably 7 to 18 gauge. Here, the number of gauges refers to the number of needles of the knitting machine between 1 inch.

In the production method of the present invention, the fibrous base material is supported on the immersion mold having a shape corresponding to the fibrous base material, and the fibrous base material is brought into contact with the polymer latex while being heated. A method in which a polymer constituting the polymer latex is infiltrated into a fiber substrate, and the infiltrated polymer is coagulated by heat of the fiber substrate, that is, a rubber layer is formed by a thermal coagulation method (thermal immersion method) Thus, a laminate including a fiber base and a rubber layer formed penetrating from one side to the other side of the fiber base is manufactured.

For example, to illustrate a protective glove as an example of a laminate, a glove-shaped fiber base is covered on a glove type as an immersion mold, and a glove-shaped fiber base is heated. The polymer which has been infiltrated by the heat of the fiber substrate while the polymer constituting the polymer latex is infiltrated into the glove-shaped fiber substrate by the thermal coagulation method, that is, by immersing the polymer latex in the polymer latex By the method of coagulating, a rubber layer composed of the polymer constituting the polymer latex is formed.

Specifically, in the case of producing protective gloves as a laminate, a polymer latex is formed into a glove shape by immersing the fiber substrate covered in the glove shape in the polymer latex in a heated state. The surface of the coated fiber substrate (the surface on the outer surface of the protective glove) is allowed to penetrate between the fibers constituting the fiber substrate, and the polymer latex is gelled by contact with the heated fiber substrate. Solidification proceeds to form a rubber layer penetrating from one side of the fiber substrate to the other side. In this case, not only the fiber base material but also the glove type may be heated, and in particular, the polymer latex which penetrates the fiber base and reaches the glove type is better along the surface of the glove type From the viewpoint that the rubber layer formed by penetrating from one surface to the other surface of the fiber substrate can be more appropriately formed, with the fiber substrate covered in a glove shape, It is preferred to heat the fiber substrate together with the glove mold and use it.

In particular, according to such a thermosensitive coagulation method, by immersing the heated fiber substrate in the polymer latex, the polymer latex is sufficiently permeated into the fiber substrate while the heat of the fiber substrate is heated. The polymer latex which has sufficiently permeated to the inside of the fiber substrate can be appropriately gelled and coagulated by the action of And thereby, the rubber layer which penetrated from the surface of a fiber base material to the back (surface which becomes the inner surface of protective gloves) of the fiber base put on a glove type can be formed appropriately. Specifically, according to the above thermal coagulation method, it is possible to continuously form a rubber layer penetrating from the surface of the fiber substrate to the back surface of the fiber substrate over substantially the whole of the fiber substrate, thereby providing flexibility It can be excellent. Moreover, according to the above thermal coagulation method, the rubber layer can be made less uneven on the surface of the fiber substrate, and the surface state can be made smooth, whereby the abrasion resistance is excellent. In addition, since the occurrence of unevenness, aggregation and the like due to the rubber layer can be effectively suppressed even on the back surface of the fiber base, the protective gloves obtained can be actually worn and used In this case, even if the rubber layer comes in contact with the hand, it is possible to reduce the unpleasant feel on the hand (the unpleasant feel due to the minute stick), thereby making it difficult to feel fatigue at the time of wearing The comfort of the can be excellent.

As a protective glove which is one embodiment of a layered product of the present invention, for example, one having a structure shown in FIG. 1 (B) can be exemplified. Here, FIG. 1 (B) is a protective glove (laminated body) in which a rubber layer formed by coagulating while penetrating the polymer latex is provided to the fiber base shown in FIG. 1 (A). Is a cross-sectional view of FIG. In the protective glove shown in FIG. 1 (B), a surface rubber layer for covering the fiber substrate is formed on the surface of the fiber substrate, and the surface rubber layer penetrates into the gaps of the fibers of the fiber substrate continuously. The surface rubber layer and the permeation rubber layer are integrally formed to form a rubber layer.

The rubber layer formed by coagulating the polymer latex may have a multilayer laminated structure by carrying out the coagulation by the above-mentioned thermal coagulation method a plurality of times.

Also, the rubber layer to be formed may be formed so as to penetrate substantially from the entire surface of the fiber substrate to the back surface of the fiber substrate, but in part, such penetrating It does not have to be in the state.

In the prior art, as a method of manufacturing a laminate having a rubber layer penetrating the fiber substrate, after the coagulant solution is attached to the fiber substrate, the weight is applied to the fiber substrate to which the coagulant solution is attached. A method (adhesion and immersion method) of forming a rubber layer on a fiber substrate by bringing a coalesced latex into contact and coagulating a polymer in the polymer latex is used. However, in such a conventional method, the polymer latex is dripped from the fiber substrate before the polymer is coagulated, and it is formed when the coagulation of the polymer proceeds in such a state. The rubber layer partially penetrates the fiber base and solidifies in a non-uniform shape in the part in contact with the immersion mold, and aggregates are formed around the penetrated part to form a lump As a result, when the resulting laminate is used as a protective glove or the like, the surface of the rubber layer has large irregularities on the inner surface of the protective glove (surface that comes in contact with the immersion mold during the production of the laminate). If the rubber layer becomes hard, it becomes inferior in durability and flexibility, and furthermore, when the rubber layer comes in contact with the hand at the time of wearing, the hand feels unpleasant to the hand. , The wearer feels tired It becomes so, there has been a problem that it is inferior in comfort at the time of mounting.

On the other hand, according to the present invention, by using the above-mentioned thermosensitive coagulation method as a method of producing a laminate having a rubber layer penetrating the fiber substrate, the fiber substrate is substantially covered throughout The rubber layer penetrating from the surface to the back surface of the fiber substrate can be continuously formed, and furthermore, on the surface of the fiber substrate, the occurrence of unevenness and aggregation caused by the rubber layer can be effectively suppressed, and the surface state Can be made smooth, so that the laminate obtained is excellent in flexibility and, in addition, when it is actually worn and used as a protective glove etc., the unpleasant feel to the hand is reduced. It can be difficult to feel fatigue at the time of wearing, and can be excellent in comfort at the time of wearing.

The thickness t ₁ of the permeation rubber layer of the laminate obtained by the production method of the present invention, from the viewpoint of durability is further improved when using the laminate as a protective glove or the like, preferably 0.05 to 1 More preferably, it is 0.10 to 0.8 mm, and more preferably, 0.15 to 0.70 mm. Incidentally, rubber layer, because in a state of penetrating the fibrous substrate, usually, the thickness t ₁ of the permeation rubber layer is a thickness equivalent to the thickness of the fiber base material, a portion of the rubber layer fibers When the base material is not penetrated (when a part of the rubber layer does not reach from the one surface of the fiber base material to the other surface), the thickness t _{1 of the} permeation rubber layer May be thinner than the thickness of the fiber substrate.

The thickness _{t 2} of the surface rubber layer, from the viewpoint of durability is further improved when using the laminate as a protective gloves and the like, preferably 0.01 ~ 3.00 mm, more preferably 0.02-2 And more preferably 0.03 to 2.0 mm.

Furthermore, the ratio of the thickness t ₁ of the permeation rubber layer to the thickness t ₂ of the surface rubber layer (t 1 _{/ t} _2), the durability at the time of using the laminate as a protective gloves, comfort of flexibility and mounting From the viewpoint of achieving a high degree of balance, preferably from 0.5 to 0.2, preferably from 0.25 to 4.80, more preferably from 0.30 to 4.60.

In addition, the thickness t of the surface rubber layer relative to the average thickness d of the base layer of the fiber base from the viewpoint of highly balancing the durability, flexibility and comfort upon wearing when the laminate is used as a protective glove etc. The ratio of ₂ (t ₂ / d) is preferably 0.10 to 0.95, more preferably 0.1 to 0.90, and still more preferably 0.15 to 0.8. The total thickness of the laminate (the thickness _{t 2} of the surface rubber layer, the sum of the base layer the average thickness d of the fiber substrate) is preferably from 0.75 to 3.70 mm, more preferably 0.75 to It is 3.5 mm. The fiber base material may differ in thickness between the portion where the degree of fiber overlap is dense and the portion where the degree of fiber overlap is sparse in the microstructure. The base material layer average thickness d of the base material is determined as the average value of the thickness of the portion of the fiber base material where the overlapping degree of the fibers is dense.

Further, the polymer constituting the polymer latex used in the present invention is not particularly limited, but 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 conjugated diene rubbers include so-called nitrile rubbers obtained by copolymerizing nitriles, isoprene rubbers, styrene-butadiene rubbers, chloroprene rubbers and the like. Among these, nitrile rubbers are particularly preferable.

The nitrile rubber is not particularly limited, but one obtained by copolymerizing an α, β-ethylenically unsaturated nitrile monomer and another copolymerizable monomer optionally used can be used.

The α, β-ethylenically unsaturated nitrile monomer is not particularly limited, but an ethylenically unsaturated compound having a nitrile group and having a carbon number of preferably 3 to 18 can be used. Examples of such α, β-ethylenically unsaturated nitrile monomers include acrylonitrile, methacrylonitrile, halogen-substituted acrylonitrile and the like, and among these, acrylonitrile is particularly preferable. These α, β-ethylenically unsaturated nitrile monomers may be used alone or in combination of two or more.

The content of the α, β-ethylenically unsaturated nitrile monomer unit in the nitrile rubber is preferably 10 to 45% by weight, more preferably 20 to 40% by weight, based on all the monomer units. Preferably, it is 30 to 40% by weight. By setting the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit in the above range, the laminate can be made more excellent in solvent resistance and more excellent in feeling. Furthermore, when the rubber layer is formed by a thermal coagulation method using a polymer latex containing such nitrile rubber by setting the content ratio of the α, β-ethylenically unsaturated nitrile monomer unit to the above range Then, the nitrile rubber is gelled and solidified better, and the rubber layer is formed better, whereby the laminate in which the rubber layer penetrates the fiber base is attached to the hand as a protective glove or the like. In use, the unpleasant feel on the hand can be further reduced, and the comfort upon wearing can be further improved.

The nitrile rubber is preferably one containing a conjugated diene monomer unit from the viewpoint of imparting rubber elasticity. Conjugated diene monomers that form conjugated diene monomer units include, for example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, chloroprene, etc. Conjugated diene monomers of 6 are preferred, 1,3-butadiene and isoprene are more preferred, and 1,3-butadiene is particularly preferred. These conjugated diene monomers may be used alone or in combination of two or more.

The content ratio of conjugated diene monomer units is preferably 40 to 80% by weight, more preferably 52 to 78% by weight, based on all the monomer units constituting the nitrile rubber. By making the content rate of a conjugated diene monomer unit into the said range, a laminated body can be made into what was excellent in solvent resistance and excellent in the feel.

In addition, the nitrile rubber is a monomer that forms an α, β-ethylenically unsaturated nitrile monomer unit, and another ethylenic unsaturated copolymerizable with a monomer that forms a conjugated diene monomer unit It may contain an acid monomer.

Such copolymerizable other ethylenically unsaturated acid monomers are not particularly limited, and, for example, carboxyl group-containing ethylenically unsaturated monomers, sulfonic acid groups-containing ethylenically unsaturated monomers, A phosphoric acid group-containing ethylenic unsaturated monomer etc. are mentioned.

The carboxyl group-containing ethylenic unsaturated monomer is not particularly limited. Ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; fumaric acid, maleic acid, itaconic acid, maleic anhydride, anhydride Ethylenically unsaturated polyvalent carboxylic acids such as itaconic acid and anhydrides thereof; Partially esterified products of ethylenically unsaturated polyvalent carboxylic acids such as methyl maleate and methyl itaconate;

The sulfonic acid group-containing ethylenic unsaturated monomer is not particularly limited, but vinylsulfonic acid, methylvinylsulfonic acid, styrenesulfonic acid, (meth) allylsulfonic acid, ethyl (meth) acrylic acid-2-sulfonate And 2-acrylamido-2-hydroxypropane sulfonic acid.

The phosphoric acid group-containing ethylenic unsaturated monomer is not particularly limited, and is, for example, propyl (meth) acrylate 3-chloro-2-phosphate, ethyl (meth) acrylate 2-phosphate, 3-allyloxy -2-hydroxypropane phosphoric acid and the like.

These other copolymerizable ethylenically unsaturated acid monomers can also be used as an alkali metal salt or ammonium salt, and may be used alone or in combination of two or more. . Among the above-mentioned other copolymerizable ethylenically unsaturated acid monomers, a carboxyl group-containing ethylenically unsaturated monomer is preferable, an ethylenically unsaturated monocarboxylic acid is more preferable, and methacrylic acid is particularly preferable.

The polymer latex can be obtained, for example, by emulsion polymerization of a monomer mixture containing the above-mentioned monomers. In the case of emulsion polymerization, commonly used secondary polymerization materials such as an emulsifier, a polymerization initiator, a molecular weight modifier and the like can be used.

The emulsifier used for the emulsion polymerization is not particularly limited, and examples thereof include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. A nonionic surfactant is preferable from the viewpoint of advancing. In particular, in the case of salt coagulation using a coagulant solution containing a coagulant such as calcium nitrate, an anionic surfactant is suitable as an emulsifier used for emulsion polymerization from the viewpoint of efficiently advancing salt coagulation. In the present invention, a nonionic surfactant is preferable and a water-soluble nonionic polymer having a cloud point of normal temperature or more and 100 ° C. or less is preferable from the viewpoint of promoting thermal coagulation more appropriately. Specific examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkyl ester and the like.
The amount of the emulsifier used for the emulsion polymerization is preferably 0.5 to 10 parts by weight, more preferably 1 to 8 parts by weight with respect to 100 parts by weight of all the monomers used.

The polymerization initiator is not particularly limited, but a radical initiator is preferable. The radical initiator is not particularly limited. For example, inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, hydrogen peroxide and the like; 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 Peroxides, organic peroxides such as t-butylperoxyisobutyrate; azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile and methyl azobisisobutyrate; . Among these, inorganic peroxides or organic peroxides are preferred, inorganic peroxides are more preferable, persulfate are particularly preferred. These polymerization initiators may be used alone or in combination of two or more.
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 all the monomers used.

The molecular weight modifier is not particularly limited, and examples thereof include: α-methylstyrene dimer; mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan and octyl mercaptan; halogenation such as carbon tetrachloride, methylene chloride and methylene bromide Hydrocarbons; sulfur-containing compounds such as tetraethylthiuram disulphide, dipentamethylenethiuram disulphide, diisopropyl xanthene disulphide, etc .; among these, mercaptans are preferred, and t-dodecyl mercaptan is more preferred. These molecular weight modifiers may be used alone or in combination of two or more.
The amount of the molecular weight modifier used varies depending on the type, but it is preferably 0.1 to 1.5 parts by weight, more preferably 0.2 to 1.0 parts by weight, based on 100 parts by weight of all the monomers used. It is a department.

Emulsion polymerization is usually 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 all the monomers used.

In the emulsion polymerization, if necessary, other polymerization auxiliary materials may be further used. As a polymerization auxiliary material, a chelating agent, a dispersing agent, a pH regulator, an oxygen scavenger, a particle size regulator and the like can be mentioned, and the type and the amount thereof are not particularly limited.

As a method of adding monomers, for example, a method of adding monomers to be used in a reaction vessel at once, a method of adding continuously or intermittently as polymerization progresses, a part of monomers is added The reaction may be carried out to a specific conversion rate, and then the remaining monomers may be continuously or intermittently added and polymerized, and any method may be employed. When the monomers are mixed and added continuously or intermittently, the composition of the mixture may be constant or may be changed.
In addition, each monomer may be added to the reaction container after previously mixing various monomers to be used, or may be separately added to the reaction container.

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

As described above, the monomers are emulsion-polymerized, and when reaching a predetermined polymerization conversion rate, the polymerization reaction is stopped by cooling the polymerization system or adding a polymerization terminator. The polymerization conversion rate at the time of stopping the polymerization reaction is usually 80% by weight or more, preferably 90% by weight or more.

The polymerization terminator is not particularly limited as long as it is generally used in emulsion polymerization, and specific examples thereof include hydroxylamine, hydroxylamine sulfate, diethylhydroxyamine, hydroxylamine sulfonic acid and alkali metal thereof Hydroxyamine compounds such as salts; sodium dimethyldithiocarbamate; hydroquinone derivatives; catechol derivatives; aromatic hydroxydithiocarboxylic acids such as hydroxydimethylbenzenethiocarboxylic acid, hydroxydiethylbenzenedithiocarboxylic acid, hydroxydibutylbenzenedithiocarboxylic acid and alkali metal salts thereof And aromatic hydroxydithiocarboxylic acid compounds such as
The use amount of the polymerization terminator is not particularly limited, but is usually 0.05 to 2 parts by weight with respect to 100 parts by weight of all the monomers used.

After termination of the polymerization reaction, if desired, unreacted monomers may be removed to adjust the solid concentration and pH.

The weight average particle size of the particles of the polymer constituting the polymer latex is usually 30 to 1000 nm, preferably 50 to 500 nm, more preferably 70 to 200 nm. By setting the weight average particle diameter of the particles of the polymer in the above range, the viscosity of the polymer latex becomes appropriate and the handleability of the polymer latex is further improved, and the moldability at the time of molding the rubber layer Is improved to obtain a laminate having a more homogeneous rubber layer.

The solid concentration of the polymer latex is usually 20 to 65% by weight, preferably 30 to 60% by weight, more preferably 35 to 55% by weight. By setting the solid content concentration of the polymer latex in the above range, the transport efficiency of the latex can be improved, and the viscosity of the polymer latex becomes appropriate to improve the handleability of the polymer latex. .

The pH of the polymer latex is usually 5 to 13, preferably 7 to 10, and more preferably 7.5 to 9. By setting the pH of the polymer latex to the above-mentioned range, mechanical stability is improved and generation of coarse aggregates at the time of transfer of the polymer latex can be suppressed, and the viscosity of the polymer latex is appropriate. As a result, the handleability of the polymer latex is improved.

In addition, as the polymer latex, it is preferable to use one in which compounding agents such as a crosslinking agent and a heat sensitive coagulant are blended. That is, it is preferable to use as a composition of latex. When the polymer latex is used as a latex composition as described above, the viscosity in the state of containing the compounding agent such as the crosslinking agent and the heat sensitive coagulant, and the compounding agent such as the emulsifying agent and the thickener described later. It is preferable to adjust so as to be in an appropriate range.

As a crosslinking agent, it is preferable to use a sulfur-based crosslinking agent. The sulfur-based crosslinking agent is not particularly limited, and powder sulfur, sulfur oxide, precipitated sulfur, colloidal sulfur, surface-treated sulfur, sulfur such as insoluble sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, dibenzothia Sulfur-containing compounds such as zyl disulfide, caprolactam disulfide, phosphorus-containing polysulfides, high molecular weight polysulfides; sulfur-donating compounds such as tetramethylthiuram disulfide, selenium dimethyldithiocarbamate, 2- (4'-morpholinodithio) benzothiazole, etc. Can be mentioned. These crosslinking agents may be used alone or in combination of two or more.

Moreover, when using sulfur as a crosslinking agent, it is preferable to use a crosslinking accelerator (vulcanization accelerator) and zinc oxide in combination.
The crosslinking accelerator (vulcanization accelerator) is not particularly limited, and examples thereof include dithiocarbamates such as diethyldithiocarbamic acid, dibutyldithiocarbamic acid, di-2-ethylhexyl dithiocarbamic acid, dicyclohexyl dithiocarbamic acid, diphenyl dithiocarbamic acid, and dibenzyl dithiocarbamic acid. Acids and their zinc salts; 2-mercaptobenzothiazole, 2-mercaptobenzothiazole zinc, 2-mercaptothiazoline, dibenzothiazyl disulfide, 2- (2,4-dinitrophenylthio) benzothiazole, 2- (N, N-diethylthio carbamoylthio) benzothiazole, 2- (2,6-dimethyl-4-morpholinothio) benzothiazole, 2- (4'-morpholino dithio) benzothiazole, 4-mole Among these, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, 2-mercaptobenzothiazole, 2-mercapto, and the like can be mentioned. Benzothiazole zinc is preferred. These crosslinking accelerators may be used alone or in combination of two or more.

The heat-sensitive coagulant may be any compound as long as it exhibits the function of coagulating the polymer latex by heating, and is not particularly limited. Epoxy-modified silicone oil, alkyl-modified silicone oil, alkylaralkyl-modified silicone oil, amino-modified silicone oil, carboxyl Silicone oils such as modified silicone oils, alcohol modified silicone oils, fluorine modified silicone oils, polyether modified silicone oils; polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane and diorganopolysiloxane diol; 1 , 1-Dihydroperfluorooctyl acrylate polymer, perfluoroalkyl ethyl acrylate-alkyl acrylate copolymer, etc. Fluoroalkyl ester polymers; and the like. By blending a thermal coagulant into the polymer latex, thermal coagulation of the polymer latex can be more appropriately progressed.

The blending amount of the heat sensitive coagulant in the case of blending the heat sensitive coagulant to the polymer latex is preferably 0.1 to 10 parts by weight, more preferably 0 based on 100 parts by weight of the polymer contained in the polymer latex. 1 to 8 parts by weight, more preferably 0.1 to 5 parts by weight. By setting the blending amount of the heat sensitive coagulant in the above range, the heat sensitive coagulation of the polymer latex can be more appropriately advanced. In the present invention, the heat-sensitive coagulant has the function of coagulating the polymer latex by heating and also has the function of a thickener for thickening the polymer latex. Therefore, also from the viewpoint of adjusting the viscosity of the polymer latex and thereby more appropriately obtaining a laminate in which the rubber layer penetrates the fiber base, the compounding amount of the heat sensitive coagulant may be in the above range. preferable. The viscosity at 25 ° C. of the polymer latex is preferably 500 to 20,000 mPa · s, more preferably 1,000 to 10,000 mPa · s. The viscosity at 25 ° C. of the polymer latex can be measured, for example, using a B-type viscometer under the conditions of 25 ° C. and 6 rpm.

In addition, an emulsifier may be further added to the polymer latex from the viewpoint of further enhancing the stability of the polymer latex. As the emulsifier, as in the case of the emulsion polymerization, nonionic surfactants are preferable, water-soluble nonionic polymers having a cloud point of 30 ° C. or more and 100 ° C. or less are preferable, and the cloud points are 45 ° C. or more and 90 ° C. The following water-soluble nonionic polymers are more preferable.

When the emulsifier is compounded into the polymer latex, the content ratio of the emulsifier compounded in the polymer latex (content ratio including those used for emulsion polymerization of the polymer latex) is preferably 20 to 0.01 weight. %, More preferably 15 to 0.02% by weight, still more preferably 10 to 0.05% by weight. When the rubber layer is formed by the thermal coagulation method using the composition of the obtained latex by setting the content ratio of the emulsifier to the above range, the rubber layer is formed better, whereby the rubber layer is a fiber group. When the laminated body formed by penetrating the material is used by attaching it to a hand as a protective glove or the like, the unpleasant feeling to the hand can be further reduced, and the comfort at the time of wearing is further improved. .

In addition to the above-mentioned thermosensitive coagulant, a thickener other than the thermosensitive coagulant may be appropriately blended in the polymer latex. Examples of such thickeners include, but are not limited to, vinyl compounds such as polyvinyl alcohol and polyvinyl pyrrolidone; cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose and carboxymethyl cellulose salts; polycarboxylic acid compounds and sodium thereof Salts; polyoxyethylene derivatives such as polyethylene glycol ether; and the like.

As a method of manufacturing the laminate of the present invention, as described above, the fiber substrate supported on the immersion mold is contacted with the polymer latex in a heated state to constitute the fiber substrate. By causing the polymer latex to sufficiently penetrate between the fibers and causing the polymer latex to come into contact with the heated fiber base and the immersion mold, gelation and solidification are carried out, and if necessary, the fiber base is It is possible to form a rubber layer penetrating from one side of the material to the other side, thereby using a method of obtaining a laminate comprising a fiber base and a rubber layer. In addition, the rubber layer may have a multilayer structure laminated a plurality of times. The method for bringing the fiber substrate into contact with the polymer latex is not particularly limited, but, for example, the fiber substrate is supported in advance by mounting the fiber substrate on a dipping mold of a desired shape, the polymer A method of immersing in latex may, for example, be mentioned. In addition, when using what added the crosslinking agent as a polymer latex, you may use what was made to ripen in advance (it is also called pre-vulcanization) as a polymer latex.

The immersion mold for supporting the fiber substrate is not particularly limited, but various materials such as porcelain, glass, metal and plastic can be used. The shape of the immersion mold may be 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, an immersion mold for covering various types of gloves, such as an immersion mold having a shape from the wrist to the fingertip, is used as an immersion mold for covering the fiber substrate. It is preferred to use.

When the fiber substrate is brought into contact with the polymer latex, the immersion die and the fiber substrate are previously heated (also referred to as preheating), and the fiber substrate supported on the immersion die is heated. , In contact with the polymer latex. The temperature (also referred to as the preheating temperature) of the fiber substrate supported on the immersion mold at the time of contacting with the polymer latex is preferably 30 to 100 ° C., more preferably 40 to 95 ° C., still more preferably 45 to 45 ° C. 90 ° C., particularly preferably 50 to 90 ° C. By setting the preheating temperature of the fiber base material supported on the immersion mold to the above range, the temperature of the fiber base material supported on the immersion mold just before contacting with the polymer latex is made the following preferable range be able to. The temperature of the fiber substrate supported on the immersion mold immediately before contacting with the polymer latex is preferably 25 to 100 ° C., more preferably 35 to 95 ° C., still more preferably 40 to 90 ° C., particularly preferably 45 It is ~ 90 ° C. By setting the temperature of the fiber base material supported on the immersion mold in the above range, the rubber layer is formed more uniformly when the rubber layer is formed by the thermal coagulation method using the polymer latex When a laminate such as a protective glove in which the rubber layer penetrates the fiber substrate is attached to the hand, the unpleasant feel to the hand can be reduced, and the comfort when attached is more enhanced. improves.

Moreover, after contacting a fiber base material with polymer latex, it is preferable to dry the polymer latex adhering to the fiber base material. Although the drying temperature in this case is not particularly limited, it is preferably 10 to 80 ° C., more preferably 15 to 80 ° C. The drying time is not particularly limited, but preferably 5 seconds to 120 minutes, more preferably 10 seconds to 60 minutes.

Furthermore, the fiber substrate may be dipped in the polymer latex and dried, and then the fiber substrate may be dipped in the polymer latex to form a multilayer structure in which the fiber substrate is laminated a plurality of times.

Moreover, when a crosslinking agent is mix | blended with polymer latex, you may make it bridge | crosslink by heating as needed.

Furthermore, when a rubber layer is formed in the state which supported the fiber base material by the immersion type | mold, a laminated body can be obtained by desorbing the fiber base material in which the rubber layer was formed from the immersion type | mold. . As the desorption method, it is possible to employ a method of peeling off from the immersion mold by hand, or peeling by means of water pressure or pressure of compressed air.
Thus, a laminate having a fiber base and a rubber layer can be obtained as an example of a laminate having a rubber layer.

Hereinafter, the present invention will be more specifically described by way of examples, but the present invention is not limited to these examples. In the following, unless otherwise stated, "parts" is by weight. The test or evaluation method of physical properties and characteristics is as follows.

Thickness t ₁ of the penetration rubber layer and thickness t _{2 of the} surface rubber layer
The protective glove (laminate) is penetrated by observing the cross section of the rubber layer of the palm portion of 12 cm from the tip of the middle finger by using an optical microscope (product name “VHX-200”, manufactured by Keyence Corporation) The thickness t _{1 of} the rubber layer and the thickness t ₂ of the surface rubber layer were measured. Referring to FIG. 1 for specific measuring method, the thickness t ₁ of the permeation rubber layer from the surface of the fiber substrate, the distance to the deepest penetration rubber, measured 10 locations, the measurement results It calculated | required by calculating a number average value. The thickness t ₂ of the surface rubber layer, the surface of the fiber substrate, the distance to the surface of the rubber layer was measured 10 locations were determined by calculating the number average value of the measurement results.

After pulling up from a state in which the liquid dripping fiber base material is immersed in the dip molding latex composition, the dip molding latex composition attached to the fiber base material is dropped from the fiber base material until it solidifies. The presence of dripping was evaluated by visually checking the scale. In addition, for the fiber base material pulled up from the dip molding latex composition, the time from when it is pulled up to when the dip molding latex composition attached to the fiber base material starts to sag (the dip molding latex composition is deformed by gravity) The time to start doing was measured.

In the case of the protective gloves (laminate), it is visually observed whether at least a part of the rubber layer which has permeated from one surface of the fiber substrate reaches the other surface through the fiber substrate. By checking, the presence or absence of strikethrough was evaluated.

Wearability Evaluation of wearability was performed by actually wearing protective gloves (laminated body) and performing simple operations such as cleaning and transportation, and then surveying the feeling of fatigue felt by the hands. We carried out for 10 people and counted the number of people who felt fatigue at the time of wearing, and evaluated it by the following criteria as fatigue degree at the time of wearing.
Good: The number of people who felt fatigue is less than 3 people Allowed: The number of people who felt fatigue is 3 or more and less than 6 people Poor: The number of people who felt fatigue is 6 or more

Wearing Comfort Wearing comfort is evaluated by actually wearing the protective gloves manufactured in the examples and comparative examples and performing simple operations such as cleaning and transportation, and then questioning the unpleasant feel felt by the hands. It went by. The survey was conducted for 10 people, and the number of people who felt an unpleasant feel due to a small stick was counted. The results are shown in Table 1.

Ten people wear flexible protective gloves (laminates), and their flexibility is evaluated by the following five-point evaluation points, and the average value of the evaluation points is determined, and the average value of the evaluation points is the best. The near thing was made into the evaluation point in each Example (For example, when average value is 4.1, it was set as "4: soft" etc.).
5: very soft 4: soft 3: somewhat soft 2: hard 1: very hard

Abrasion Resistance The abrasion test was evaluated according to the method described in EN 388, using a Martindale-type abrasion tester (product name “STM633, manufactured by SATRA”). Specifically, with respect to a protective glove (laminate), friction was repeated while applying a predetermined load, and the number of times of friction until breakage was obtained. It is divided into levels from level 0 to level 4 according to the number of times of friction leading to breakage, and the higher the level, the better the abrasion resistance.
LEVEL 4: Number of rotations 8,000 or more LEVEL 3: Number of rotations 2,000 or more, less than 8,000 rotations LEVEL 2: Number of rotations 500 or more, less than 2,000 rotations LEVEL 1: Number of rotations 100 or more, 500 Less than rotation LEVEL 0: less than 100 rotations

Example 1
Preparation of Latex Composition for Dip Molding A latex of nitrile rubber (a) having a content of acrylonitrile unit of 35% by weight as a polymer latex (trade name "Nipol LX511A, manufactured by Nippon Zeon Co., Emulsifier: nonionic surface activity Preparation, and 100 parts of nitrile rubber (a) in the latex, each in terms of solid content, in terms of solid content, polyoxyethylene alkyl ether as an emulsifier (trade name "Emulgen 709", cloud point 56 ° C, manufactured by Kao Corporation 2.50 parts, polyether-modified silicone oil (trade name "TPA 4380" manufactured by Toshiba Silicone Co., Ltd.) as a heat sensitive coagulant, 0.3 parts, antifoamer (trade name "SM5512" manufactured by Toray Dow Corning Co., Ltd.) 0.01 parts, colloidal sulfur (made by Hosoi Chemical Industries, Ltd.) 1.00 parts, dibutyl dithiocarbamic acid An aqueous dispersion of each compounding agent was prepared to have 0.50 parts (manufactured by Ouchi Emerging Chemical Industry Co., Ltd.), 1.50 parts of zinc oxide and 3.00 parts of titanium oxide, and the prepared aqueous dispersion was added To obtain a latex composition. When the aqueous dispersion of each compounding agent was added, a predetermined amount of the aqueous dispersion of each compounding agent was slowly added while stirring the latex. Thereafter, the solid content concentration of the latex composition is adjusted to 45% by weight, and then aging (also called pre-vulcanization) is performed under conditions of a temperature of 30 ° C. for 48 hours to use a B-type viscometer. A dip molding latex composition having a viscosity of 1,800 mPa · s measured at 25 ° C. and 6 rpm is obtained.

Production of Laminate (Protective Glove) A glove-shaped fiber base (material: nylon, base layer average thickness of fiber base d) coated on a metal glove type using the obtained latex composition for dip molding A rubber layer was formed by a thermal coagulation method at 0.70 mm, 13 gauge). Specifically, the fiber base covered with the metal glove mold is preheated to 76 ° C., immersed in the above dip molding latex composition for 2 seconds, and pulled up from the dip molding latex composition, as described above. Evaluation of dripping was performed according to the method described above. The temperature of the fiber base immediately before dipping was 75.degree. Then, the rubber composition was formed by drying the dip molding latex composition attached to the fiber substrate under conditions of a temperature of 80 ° C. for 30 minutes. Next, heat treatment was performed at a temperature of 100 ° C. for 60 minutes to crosslink the nitrile rubber in the rubber layer to form a rubber layer. Next, the fiber base on which the rubber layer was formed was peeled off from the metal glove mold to obtain a protective glove (laminate). About the obtained protective glove (laminated body), according to the method mentioned above, measurement of thickness t ₁ of a penetration rubber layer, measurement of thickness t ₂ of a surface rubber layer, strike-through, wearing property (wearing degree at wearing), wearing comfort Each evaluation of the property, the flexibility, and the abrasion resistance was performed. The results are shown in Table 1.

Example 2
The heating temperature (preheating temperature) of the fiber base covered with the metal glove mold was changed from 76 ° C. to 71 ° C. when the metal glove mold covered with the fiber base was immersed in the dip molding latex composition. A protective glove (laminate) was obtained and evaluated in the same manner as in Example 1 except for the above. The temperature of the fiber base immediately before dipping was 70.degree. The results are shown in Table 1.

Example 3
The heating temperature (preheating temperature) of the fiber base covered with the metal glove mold was changed from 76 ° C. to 56 ° C. when the metal glove mold covered with the fiber base was immersed in the dip molding latex composition. A protective glove (laminate) was obtained and evaluated in the same manner as in Example 1 except for the above. The temperature of the fiber base immediately before dipping was 55.degree. The results are shown in Table 1.

Comparative Example 1
A latex of nitrile rubber (a) (trade name "Nipol LX511A", manufactured by Nippon Zeon Co., Ltd.) having a content ratio of acrylonitrile units of 35% by weight is prepared as a polymer latex, and 100 parts of nitrile rubber (a) in the latex To 0.01 parts of a defoaming agent (trade name “SM5512” manufactured by Toray Dow Corning Co., Ltd.), 1.00 parts of colloidal sulfur (manufactured by Hosoi Chemical Industry Co., Ltd.), and zinc dibutyldithiocarbamate. An aqueous dispersion of each compounding agent was prepared to have 0.50 parts (manufactured by Ouchi Emerging Chemical Industry Co., Ltd.), 1.50 parts of zinc oxide and 3.00 parts of titanium oxide, and the prepared aqueous dispersion was added To obtain a latex composition.
When the aqueous dispersion of each compounding agent was added, a predetermined amount of the aqueous dispersion of each compounding agent was slowly added while stirring the latex. Then, aging (also referred to as pre-vulcanization) was performed under conditions of a temperature of 30 ° C. and 48 hours. Then, to the latex composition after aging, sodium polyacrylate (trade name “ARON A-7100”, manufactured by Toagosei Co., Ltd.) as a thickener is further added at a ratio of 0.4% by weight. A dip molding latex composition having a viscosity of 1,500 mPa · s measured under conditions of a temperature of 25 ° C. and a rotational speed of 6 rpm was obtained using a B-type viscometer.

Next, a rubber layer was formed on the glove-shaped fiber base material (material: nylon, base layer average thickness d of fiber base material: 0.70 mm, 13 gauge) by the adhesion immersion method. Specifically, after heating a glove-shaped fiber substrate covered with a metal glove type to 42 ° C., a calcium nitrate methanol solution (calcium nitrate concentration: 2.0% by weight) as a coagulant solution is used. It was immersed for a second, pulled up from the coagulant solution, and dried at a temperature of 30 ° C. for 60 seconds. Thereafter, the fiber base covered with the metal glove mold is dipped in the above dip molding latex composition for 3 seconds, pulled up from the dip molding latex composition, and then dried under conditions of temperature 30 ° C. for 30 minutes. Formed a rubber layer. The temperature of the fiber base immediately before dipping was 23 ° C. Next, heat treatment was performed at a temperature of 100 ° C. for 60 minutes to crosslink the nitrile rubber in the rubber layer to form a rubber layer. Next, the fiber base on which the rubber layer was formed was peeled off from the metal glove mold to obtain a protective glove (laminate). The obtained protective gloves (laminate) were evaluated in the same manner as in Example 1. The results are shown in Table 1. The protective gloves of Comparative Example 1, the thickness t ₁ of the permeation rubber layer measured by the method described above has become thinner than the base layer the average thickness of the fiber base material d (0.70 mm), part Betrayal had occurred.

Comparative example 2
Nitrile rubber (b) (trade name “Nipol LX550L”, Nippon Zeon, having a content ratio of acrylonitrile units of 27% by weight, instead of nitrile rubber (a), as nitrile rubber for producing a latex composition for dip molding A protective glove (laminate) was obtained and evaluated in the same manner as in Comparative Example 1 except that a company-made product was used. The temperature of the fiber base immediately before dipping was 22 ° C. The results are shown in Table 1. The protective gloves of Comparative Example 2, the thickness t ₁ of the permeation rubber layer measured by the method described above has become thinner than the base layer the average thickness of the fiber base material d (0.70 mm), part Betrayal had occurred.

As shown in Table 1, when the above-mentioned thermosensitive coagulation method is used as a method of producing a laminate having a rubber layer penetrating the fiber substrate, occurrence of dripping of the resulting laminate is prevented. Rubber layer was well formed, and was excellent in the mounting property, the mounting comfort, the flexibility and the abrasion resistance (Examples 1 to 3).

On the other hand, as a method of producing a laminate having a rubber layer penetrating the fiber substrate, after the coagulant solution is attached to the fiber substrate, the polymer latex is brought into contact with the fiber substrate to which the coagulant solution is attached. When the method of forming the rubber layer on the fiber base by coagulating the polymer in the polymer latex is used, dripping of the polymer latex occurs when the rubber layer is formed. As a result, the resulting laminate was inferior in both the mounting property and the flexibility (Comparative Examples 1 and 2). In particular, in the case of using a nitrile rubber having a relatively small content ratio of acrylonitrile units as a nitrile rubber for producing a latex composition for dip molding, the obtained laminate was also inferior in wearing comfort (Comparative example 2).

Claims

A method for producing a laminate, comprising: a base material; and a rubber layer formed to penetrate from one surface of the base material to the other surface of the base material,
The above-mentioned polymer which permeated the polymer which constitutes the above-mentioned polymer latex to the above-mentioned base material by making the above-mentioned base material supported on the mold for immersion contact the polymer latex in a heated state The manufacturing method of the laminated body provided with the coagulation | solidification process which forms the said rubber layer by coagulating.
The method for producing a laminate according to claim 1, wherein the polymer latex is brought into contact in a state in which the base material supported on the immersion mold is heated to 30 ° C. or more in the coagulation step.
The method for producing a laminate according to claim 1 or 2, wherein the polymer latex is brought into contact in a state where the substrate supported on the immersion mold is heated to 45 ° C or more in the coagulating step.
The method for producing a laminate according to any one of claims 1 to 3, wherein the polymer constituting the polymer latex is a nitrile rubber.
The method for producing a laminate according to any one of claims 1 to 4, wherein the polymer latex contains a nonionic surfactant.
A method of producing a protective glove using a laminate obtained by the method according to any one of claims 1 to 5.