JPS62177043A - Foam forming composition - Google Patents

Abstract

PURPOSE:A composition forming foam which can be freely molded into an industrially advantageous shape, showing high strength and high durability, containing water dispersions of butadiene high polymer by specific emulsion polymerization method. CONSTITUTION:A composition containing water dispersions of butadiene high polymer obtained by emulsion polymerization wherein 100pwt.wt. monomers consisting of butadiene and an ethylenic unsaturated monmer copolymerizable butadiene are collectively fed to a polymerization system and an alkylmercaptan is added to the system at 5-30wt% polymerization rate. Methyl acrylate, styrene, crotonic acid, etc., are used as the ethylenic unsaturated monomer. The alkylmethylmercaptan has 3-18 carbons, n-octylmercaptan, n- tetradecylmercaptan, etc., are used as the alkylmercaptan and the amount of it blended is 0.05-2.0pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a foam-forming composition containing an aqueous butadiene polymer dispersion obtained by a special emulsion polymerization method.
Furthermore, the present invention relates to a composition for forming a foam that can stably form a modified high-strength foam.

Conventional technology Traditionally, natural and synthetic resin aqueous dispersions are added with foaming agents, coagulants, crosslinking agents and other additives, mechanically foamed, and then applied onto a substrate or poured into a mold. A method of forming a foam by drying, coagulating, and curing is known. Examples of such aqueous natural and synthetic resin dispersions include natural rubber latex δ tyrene-butadiene copolymer aqueous dispersions, acrylonitrile-7'' tadiene copolymer aqueous dispersions, and acrylic acid ester copolymer aqueous dispersions. The formed foams are used in a variety of applications due to their structural advantages such as light weight, wall thickness, texture, and feel.

However, many of these foams have poor mechanical strength and durability, and in order to be used in a wider range of applications, improvements such as higher strength and durability are required. For example, natural rubber and butadiene copolymers improve durability such as light resistance and heat resistance, and mechanical strength, while acrylic ester copolymers improve mechanical strength, solvent resistance, and cold resistance. It is necessary to improve properties such as properties or elasticity.

On the other hand, various methods have been proposed for forming foams from aqueous polyurethane dispersions, and these foams are attracting attention as having commercial performance that improves the above-mentioned drawbacks. However, polyurethane aqueous dispersions are not satisfactory in terms of foam moldability using conventionally proposed mechanical foaming methods, and the resin's inherent properties have not yet been utilized in a wide range of applications, and improvements are needed. For example, it is unsatisfactory in terms of stable and wide foaming moldability that allows the formation of foams with high expansion ratios and high coating thicknesses, and improvements are needed.

In this way, when forming a foam from an aqueous synthetic resin dispersion, it has both excellent foam physical properties such as high strength and durability, and foam moldability that allows it to be freely formed into stable and industrially useful forms. Although there has been a strong demand for this to be done, it has not been possible to do so.

A key and difficult technical issue in such prior art is foam moldability. That is, when foaming an aqueous dispersion, bubbles are generated and maintained finely and uniformly, and the bubbles are coalesced from an aqueous dispersion that is essentially a weak aqueous dispersion that forms partition walls containing bubbles. Alternatively, the objective is to form a resin film strong enough to withstand permanent bubble retention without causing the bubbles to disappear. That is, contradictory properties are required, firstly, the ability to stabilize the dispersion of an aqueous dispersion, and secondly, the ability to destabilize the dispersion to quickly fuse the dispersed resin particles. Therefore, the method of improving physical properties by combining different types of aqueous dispersions, which is adopted in non-foaming systems, is similar to that in foaming systems.
This was difficult because the dispersion stabilizing ability and destabilizing ability of each aqueous dispersion were different. In fact, the mixed aqueous dispersion of a polyurethane aqueous dispersion and a styrene-butane diene copolymer aqueous dispersion according to the prior art significantly thickened during mechanical foaming and solidified into a tofu-like shape, or a large number of coarse bubbles were mixed in. The only product I could get was a foam with no commercial value. Particularly when molding is performed under a high expansion ratio and a high coating thickness, the commercial value of the foam is diminished due to the coarsening and disappearance of the bubbles. Of course, if one aqueous dispersion is kept in an extremely small amount, or two aqueous dispersions of the same type are used, or if the foaming ratio is low or the coating thickness is low (for example, about 1u thick), the product value may be slightly reduced. Although it is not impossible to obtain something, it has not been possible to significantly improve both the physical properties and foam moldability of the foam, and it has not been possible to satisfy the above-mentioned requirements.

The present inventors have developed a foam made from an aqueous synthetic resin dispersion that has both significantly improved foam physical properties such as strength and durability, and foam moldability that allows it to be freely molded into stable and industrially useful forms. As a result of intensive research on moldability, we discovered that using an aqueous dispersion of a butadiene polymer obtained by a specific emulsion polymerization recipe can impart excellent foam properties and foam moldability, resulting in the present invention. did.

That is, the present invention uses a monomer 100 having a composition consisting of butadiene and an ethylenically unsaturated monomer copolymerizable with butadiene.
A foam-forming composition comprising an aqueous polymer dispersion of a butadiene polymer obtained by charging parts by weight all at once, adding alkyl mercaptan when the polymerization rate is 5 to 30% by weight, and carrying out emulsion polymerization. provide something.

Among the monomers emulsion polymerized to obtain the aqueous polymer dispersion in the present invention, butadiene is used to internally plasticize the aqueous polymer dispersion and to impart good elasticity to the film.

The ratio is preferably between 5 and 90 with respect to the monomer mixture.
% by weight is used.

Examples of ethylenically unsaturated monomers copolymerizable with butadiene in the present invention include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, and methacrylate. Butyl, pentyl acrylate, pentyl methacrylate, hexyl acrylate, hexyl methacrylate, heptyl acrylate, heptyl methacrylate, octyl acrylate, octyl methacrylate,
Acrylic acid alkyl esters and methacrylic acid alkyl esters exemplified by octadecyl acrylate and octadecyl methacrylate; ethylenic esters exemplified by styrene, α-methylstyrene, vinyltoluene, chlorostyrene, 2,4-dibromostyrene, etc. Unsaturated aromatic monomers; unsaturated nitriles such as acrylonitrile and methacrylonitrile; acrylic acid, methacrylic acid, crotonic acid, maleic acid and its anhydrides, fumaric acid, itaconic acid, and unsaturated dicarboxylic acid monoalkyl esters; P.J., t.
is an ethylenically unsaturated carboxylic acid such as monomethyl maleate, monoethyl fumarate, mono-n-butyl itaconate;
Vinyl esters such as vinyl acetate, vinyl propionate, etc.; Vinylidene halide such as vinylidene chloride, vinylitine bromide, etc.; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-methacrylate
Hydroxyalkyl esters of ethylenically unsaturated carboxylic acids such as hydroxyethyl, etc.: Glycidyl esters of ethylenically unsaturated carboxylic acids such as glycidyl acrylate, glycidyl methacrylate, etc., and acrylamide, methacrylamide, N-methylolacrylamide, N-
Examples include radically polymerizable monomers such as methylolmethacrylamide, N-butoxymethylacrylamide, and diacetone acrylamide.

Together with butadiene, these monomers can internally plasticize the aqueous polymer dispersion, give hardness and strength to the film, and improve the mechanical stability and freeze stability of the aqueous polymer dispersion. It is used to improve adhesive properties and adhesive strength. In addition, the ratio is 10 to 95 Tt to the monomer mixture,
It is preferable to use % by weight, but when the composition for emulsion polymerization of the present invention comprising butadiene and a monomer copolymerizable with butadiene contains an unsaturated carboxylic acid, the composition should be used in an amount of 1 to 10% by weight. 6% Tsuyu is preferred, especially when used for foam formation, 25% to 25%
90 weight percent, monomer copolymerizable with butadiene 10-7
It is preferable that the amount of the unsaturated carboxylic acid is 5% by weight, and particularly preferably 1 to 10% by weight of the total monomers.

The alkyl mercaptan used in the present invention is preferably an alkyl mercaptan having 6 to 18 carbon atoms,
Examples include n-octylmercaptan, n-dodecylmercaptan, n-tetradecylmercaptan, n-octadecylmercaptan, tert-dodecylmercaptan, and the like.

These specific alkyl mercaptans are added at a polymerization rate of 5 to 60% by weight after the start of polymerization, but if the polymerization rate is less than 5% by weight, the particle size cannot be increased and the solidity is high. Differentiation is difficult, and if it exceeds 30% by weight, a large amount of coagulation will occur in the dispersion, making it impractical. Particularly preferably 5 to 19% by weight. These specific alkyl mercaptans are used in an amount of 1L05 to 2.0 parts by weight based on 100 parts by weight of the total monomers, although there are no particular restrictions on the amount used.

These behaviors of alkyl mercaptans are considered as follows. As the emulsion polymerization progresses, the micelles disappear and the number of particles in the latex is determined, and from then on, the generated particles become 1 case, but when the 1 content is 5 to 60% by weight, the polymerization place changes from micelles to particles. In addition, the amount of monomer supplied is large, and the polymerization rate is also high. At this time of year @
It is presumed that by adding the alkyl mercaptan that acts as a transfer agent, the low molecular weight polymer formed on the particle surface becomes swollen and promotes the coalescence of p1 particles, resulting in the formation of large particles. be done. As a result, it can be usefully used for forming foams that require high concentration.

The aqueous polymer dispersion in the present invention is produced by bulk charging emulsion polymerization under reaction conditions of reaction temperature D to 100° C. and reaction time 5 to 15 hours. For example, by emulsifying and dispersing the above monomer mixture in water, a free radical generating catalyst,
For example, K P S (K, 820g), A P S (
(NH4)tSzOs), an aqueous catalyst such as hydrogen peroxide solution,
An oil-based catalyst such as t-butyl hydroperoxide or cumene hydroperoxide, preferably 50 to 70
Emulsification may be carried out at 1°C. In addition, surfactants, emulsifiers, and
Inorganic electrolytes and other additives can be used as needed. In addition, this polymer aqueous dispersion immediately after 1 cup has a viscosity of 60~
It is 300cps. In order to improve excellent stability, it is preferable to adjust the pH to 9.0 ICj51 with an alkaline substance or solution after the polymerization is completed. The aqueous polymer dispersion obtained according to the present invention can be concentrated to a high solids content, for example, by a method such as stripping.
Low viscosity 30-30Dcps even at 5-65% by weight
(25°C), so workability is good. The aqueous butadiene polymer dispersion obtained in this manner can be used in combination with other aqueous dispersions, and the foam obtained by the present invention has excellent mechanical strength, heat resistance, and cold resistance. It can exhibit excellent physical properties such as light resistance, solvent resistance, and elasticity that cannot be obtained conventionally.

Other aqueous dispersions that can be added to the composition of the present invention include polyolefin-based (polypropylene, polyethylene), fluororesin-based, polyacetal-based, phenolic resin-based, epoxy resin-based, alkyd resin-based, polyester resin-based,
Polyurethane type, conjugated diene and/or vinyl type polymer (ethylene-vinyl acetate type, acrylic type, modified S B
R, modified NBR) alone or in a mixed aqueous dispersion, preferably a polyurethane aqueous dispersion, a conjugated diene and/or a vinyl polymer aqueous dispersion.

The mixing ratio of the other aqueous dispersion [I] that can be added to the present invention and the butadiene polymer aqueous dispersion +10 of the present invention is preferably (I)/(II)-80/20 to 10/90 ( solid content weight ratio). The solid content of the mixed liquid at that time is 40 to 6
0% by weight, preferably 45-55% by weight.

131 Aqueous polyurethane dispersions that can be used in the present invention are already known and can be produced by various methods. For example, emulsified polyurethane solvent solutions,
As basically described in Publication No. 1141, a polyhydroxy compound having a hydroxyl group at the end is reacted with an organic polyisocyanate in excess of the stoichiometric amount, and then the obtained prepolymer is placed in an aqueous dispersion medium. It is also possible to use an aqueous polyurethane dispersion obtained by emulsifying the prepolymer with a surfactant and adding a chain extender thereto to extend the chain of the prepolymer.

Such polyhydroxy compounds usually have a molecular weight of 300
-4000, preferably 600-3000, typical examples of which include polyether polyols, polycarbonate polyols and polyester polyols.

Polyether polyols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-
Globrene gelicol, trimethylene glycol, 1.
3-butylene glycol, tetramethylene glycol,
hexamethylene glycol, decamethylene glycol,
Glycerin, sorbitol, sucrose, aconitic acid, trimellitic acid, hemimellitic acid, phosphoric acid, ethylenediamine, propylene diamine, diethylene triamine, triisopropanolamine, pyrogallol, dihydrobenzoic acid, hydroxyphthalic acid, 1.2.3-propane One kind of monomer such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, cyclohexylene, etc. using 1' pJ or more of a compound having at least two active hydrogen atoms such as trithiol as an initiator. or more by addition polymerization using a conventional method.

On the other hand, polyester polyols include ethylene glycol, diethylene glycol, triethylene glycol,
At least 2 such as 1°2-propylene glycol, trimethylene glycol, 1°3-butylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, etc.
one or more compounds having hydroxyl groups, malonic acid, maleic acid, succinic acid, adipic acid,
One or more compounds having at least two carboxyl groups, such as tartaric acid, pimelic acid, sebacic acid, oxalic acid, phthalic acid, terephthalic acid, hexahydrophthalic acid, aconitic acid, trimellitic acid, hemimellitic acid, etc. It is produced by condensation polymerization of two or more types by a conventional method.

Polyhydroxy compounds such as polyether polyols and polyester polyols can be used alone or in combination of two or more. 2
-7'robilene glycol, trimethylene glycol,
It can be used in admixture with low molecular weight polyols such as 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol and the like.

Examples of organic polyisocyanates include aliphatic, alicyclic or aromatic polyisocyanates, such as 2,4-)lylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diincyanate, m
- Phenylene diisocyanate, xylylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, 1,
4-Cyclohexylene diisocyanate, 4,4'-dicyclohexyl diisocyanate, 3.3'-dimethyl-4,4'-biphenylene diisocyanate, 3.3'
-dimethoxy-4,4'-biphenylene diisocyanate, 6,3'-dimethoxy-4,4'-vinenyl diisocyanate), Nokoban Te3, 3'-dichloro-4
, 4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, diphenyl-2,4,4-) diisocyanate, and the like.

Chain extenders are compounds having at least two active hydrogen atoms capable of reacting with incyanate groups, such as ethylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol, monoethanolamine, ethylenediamine, triethylenediamine, 1.2-propylenediamine, hexamethylenediamine, N-ethanolethylenediamine, N,N-jetanolethylenediamine, m-phenylenediamine, 2
．． Representative examples include glycols, alkanolamines, and diamines such as 4-tolylene diamine, bis-4-aminophenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, piperazine, and 2-methylbiperazine. However, the reaction product of 1 mole of alkylene diamine and 2 moles of acrylamide, 1 mole of alkylene diamine
A reaction product of 2 moles of acrylonitrile can also be used.

The concentration of the polyurethane aqueous dispersion in the present invention is not particularly limited, but considering the economical efficiency during drying and the homogeneity of the foam, it is 60 to 60% by weight, preferably 40 to 50% by weight.
is appropriate.

Foaming aids added to the composition containing the aqueous butadiene thread polymer dispersion of the present invention include sodium laurate, coconut oil soap, sodium myristate, ammonium stearate, sodium palmitate, sodium oleate, ? i6M alcohol sulfate sodium,
Higher fatty acid sodium amidoalkyl sulfonate, saponin, gelatin, casein, etc. are used. Perfume surfactants having 1 to 20 carbon atoms are also used.

As the viscosity modifier, casein, alginate, gum arabic, bentonite, clay, carboxylated methylcellulose, polyvinyl alcohol, polyvinylpyrrolidone copolymer, polyethylene oxide polymer, polyacrylic acid emulsion, etc. are used. The amount of these added is usually 11 to 5 parts, preferably α5 to 3 parts. The viscosity of the adjusted composition is suitably 1000 to 15000 cp.

As the crosslinking agent, water-soluble melamine-formaldehyde resin, water-soluble urea-formaldehyde resin, water-soluble or water-dispersible epoxy resin, incyanate resin, aziridine compound, etc. are used.

Addition of silicone oil is effective in order to fully reflect the elastic properties of the foam, which are similar to those of polyurethane resin. Examples include dimethyl silicone oil, methylphenyl silicone oil, amine-modified silicone oil, and polyether-modified silicone oil. The amount added is 1 per 100 parts by weight of the composition.
1 to 6 parts by weight are used. Silicone oil that has been previously made into an aqueous dispersion may also be used.

In addition, colorants, fillers, anti-aging agents, anti-mold agents, etc. may be used within the range that does not impair the purpose of the present invention.

The composition containing the aqueous polymer dispersion, which has been adjusted to a suitable viscosity, is then foamed in a rubber latex in a known manner to convert it into a homogeneous, fine-celled composition.

In this case, mechanical foaming is most common, but the type of foaming machine is not particularly limited, and those generally used for foaming rubber latex can be used.

- Give an example as follows. The viscosity is adjusted to an appropriate level, and if necessary, foaming aids, viscosity modifiers, foam stabilizers,
The composition containing a crosslinking agent and the like is fed into a foaming machine using a gear pump or the like. Meanwhile, gas (usually air) is pumped into the foaming machine by a compressor or the like. Each flow rate is controlled by a gauge. The composition and gas injected into the foaming machine are mixed there, and the injected gas is finely divided and dispersed in the composition by a rotating cylinder, and the foamed composition is then removed from the foaming machine. come out. The incorporation of gas (the ratio of gas to the composition), which is related to the density of the composition foam obtained by drying, is done by controlling the amount of gas injected, and the thickness of the bubbles is determined by the composition. Controlled by viscosity and cylinder rotation speed. (Note that a hand mixer is experimentally sufficient for foaming the composition.)
In this case, the expansion ratio is generally 1.5 to 6.

After foaming in this manner, the composition is poured into a mold or cast onto a substrate and dried. In this case, a doctor knife is generally used to coat the substrate to a uniform thickness.

The base materials include fiber fabrics, fiber knitted fabrics, textile products such as raised fabrics, flocked fabrics, non-woven fabrics, paper, polyvinyl chloride sheets, leather sheets, release paper, films with release properties such as polypropylene and polyester, and glass. Examples include plates, metal plates, and the like.

By drying the applied composition containing bubbles, the dispersion medium (water) is removed, and a foam material having uniform and fine bubbles is obtained. The drying temperature is 60-160°C, preferably 100-140°C. When the composition is cured by heat treatment, the drying is followed by heat treatment.

Foams made from the composition of the present invention can be formed on various substrates and used for various purposes. For example, bags, clothing, shoes,
Synthetic leather for shoes, artificial leather, other imitation leather - coated cloth, carpets (backings), kotatsu mats,
Entrance/JJT bathroom mats, sponge sheets or other molded products, usage that not only forms foam but also serves as a contact layer while forming the foam, and use that embosses after forming the foam. Methods and the like may also be included. For example, the base material (I
A foam layer is formed between I and the base material trn and the base materials are fixed together, or a foam is formed on the top of one base material and the base material and another dense base material are formed at the same time. and foam flocking, in which the foam also serves as a binder for the pile. In addition, the formed foam is subjected to post-emboss processing to give a secondarily uneven pattern. This is an example of another characteristic of the foam of the present invention, which is the good adhesion of the cell walls under constant heat/pressure, and the high elasticity of the remaining portion with a high expansion ratio.

The above examples of applications and uses are not limiting, but merely examples that take advantage of the wide range of industrially advantageous foam-forming features of the present invention.

Next, the present invention will be specifically explained with reference to Examples. still,
All parts and percentages shown in the text are by weight unless otherwise specified.

Example 1 In a nitrogen-substituted autoclave, 120 parts of ion-exchanged water, 0.5 parts of sodium hydroxide, 42 parts of butadiene, 50 parts of styrene, 5 parts of methyl methacrylate, 3 parts of itaconic acid
1 part, 0.5 part of sodium alkylbenzene sulfonate, and 1 part of ethylenecyaminetetrabutyric acid a were added, and at a polymerization temperature of 60° C., 10 parts of ammonium persulfate was added to start polymerization.

The pH at this time was 5.3. Polymerization ≠ 3 hours after the start, the polymerization rate was 15%, and tertiary dotesyl mercaptan to
1 part was added to the reaction vessel and the reaction was continued for an additional 12 hours. Next, the pH was adjusted to a viscosity of 8000 cps by adding an aqueous solution of silmethylcellulose with potassium hydroxide, and then 1 part of silicone oil, 3 parts of glycerol triglycidyl ether
1 part and 4 parts of ammonium stearate were added and mixed uniformly.

This mixture was foamed using a continuous mechanical foaming machine (manufactured by Suga Kikai), applied onto cotton broadcloth, and heat-treated at 120° C. for 8 minutes to obtain a foamed sheet with uniformly fine cells and a smooth surface. Table -
1 shows the physical properties.

Example 2 A polymer aqueous dispersion (A-2) (solid content 55.0 %,
A viscosity of 100 cps) was obtained. The same formulation as in Example 1 (viscosity: 8200 cps) was carried out, and foaming was carried out in the same manner to obtain a foamed sheet. Physical properties are shown in Table 1.

Comparative Example 1 Polymerization was carried out using the same composition as in Example 1, except that 10 parts of tertiary dodecyl mercaptan was added at the start of polymerization.

Note that tertiary dodecyl mercaptan was not added midway. Further, the pH was adjusted and concentrated in the same manner as in Example 1 to obtain a polymer aqueous dispersion (A-3) (solid content: 5
5.0%, viscosity 2800 cps). Example 1
The same formulation as (viscosity 900 Dcps) was carried out, and the same foaming was carried out to obtain a foamed sheet. The physical properties are shown in Table-1.

Comparative Example 2 Polymerization rate of 10 parts of Tajaryde tyral mercaptan was 6
Polymerization was carried out using the same composition as in Example 1 except that it was added at 0%. Furthermore, pH adjustment and concentration were performed in the same manner as in Example 1 to obtain a polymer aqueous dispersion (A-4) (solid content 55.0
%, viscosity 1530 cps). The same formulation as in Example 1 was carried out (viscosity: 9200 cps), and the same foaming was carried out to obtain a foamed sheet. The physical properties are shown in Table-1.

Reference example 1 Polyoxypropylene glycol (average molecule 'J110
00) and 175 parts of tolylene diisocyanate were mixed and reacted at 80°C for 2 hours to produce a NCO/f712 prepolymer, and 270 parts of toluene was added to form a homogeneous solution. 140 parts of this prepolymer solution per minute
While slowly stirring the ethylene oxide addition mole emulsion in a mixer running at 2000 rpm, add the following:
An aqueous chain extender solution prepared by dissolving 74,782 parts of 1.6-hexamethylene diene in 30 parts of water was added dropwise over a period of 2 minutes. After dropping, stirring was continued for 2 hours to obtain a stable polyurethane emulsion (B-1). The solid content concentration was 46% and the viscosity was 850 centibois.

Example 3 50 parts of the polymer aqueous dispersion (A-1) created in Example 1 and the polyurethane emulsion (B-1) created in Reference Example 1
)-29 = 50 parts Mixed emulsion was blended in the same manner as in Example 1 (viscosity 8000 cps) and foamed in the same manner to obtain a foamed sheet. Table 1 shows the physical properties. This foamed sheet was found to be excellent in abrasion resistance, light resistance, etc.

Example 4 and Comparative Example 3.4 Polymer aqueous dispersion (A-2) created in Example 2 and polymer aqueous dispersion (A-3) (A-4) created in Comparative Example 1.2
A mixed emulsion of 50 parts each of the polyurethane emulsion (B-1) prepared in Reference Example 1 was blended in the same manner as in Example 1. The viscosity is 80 each.
00 cps.

'1020 cps, 7500 cps. Further, foaming was performed in the same manner as in Example 1 to obtain a foamed sheet. The physical properties of each are shown in Table-1.

sub Cao

Claims (1)

[Claims] 1. 100 parts by weight of a monomer having a composition consisting of butadiene and an ethylenically unsaturated monomer copolymerizable with butadiene are charged at once, and the alkyl mercaptan is prepared at a polymerization rate of 5 to 30.
% by weight of a butadiene-based polymer aqueous dispersion obtained by emulsion polymerization.