JP2961207B2 - Method for producing copolymer latex - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a copolymer latex, and an adhesive composition, a paper coating composition and a carpet backing using the copolymer latex obtained by the method. The present invention relates to an adhesive composition and an adhesive composition for a lock fiber substrate.

[0002]

BACKGROUND OF THE INVENTION The so-called butadiene-based copolymer latex containing butadiene as a main component is widely used as a binder in the field of paper coating, back sizing of carpets or rock fiber base materials. Is well known.

[0003] The performance required of the binder in each application varies widely, and the composition and structure of the butadiene-based copolymer latex are generally changed accordingly.

[0004] These copolymer latexes are generally produced by emulsion polymerization. At this time, slight differences are observed depending on the composition of the monomer mixture constituting the copolymer latex and the types and amounts of various additives. However, there is a problem that a fine coagulated product is generated in the copolymer latex.

[0005] Such fine coagulates adhere to the reactor and have various adverse effects on the reaction process, and also cause various adverse effects in each end use.

That is, in the field of paper coating, if such solidified matter is large, problems such as streak trouble during blade coating, applicator stain, stain during calendering, blanket pile during printing, and the like occur.

[0007] Further, these copolymer latexes
Adhesives for carpet backing such as tufted carpets and needle punch carpets and car cushion materials,
It is also used as an adhesive for rock fiber substrates used in applications such as civil engineering mats and industrial filters, but even in this case, the fine coagulated material in the copolymer latex adversely affects the adhesive strength and water resistance. Exert.

[0008] As described above, the finely coagulated product in the copolymer latex is usually removed by a filtration step or the like because it causes contamination of the reactor and causes various adverse effects in each end use.

However, the filtration step is also complicated, and the amount of the fine coagulated material to be removed is limited. Therefore, it is difficult to completely remove the fine coagulated material, and the productivity must be reduced. I was

Further, in the field of paper coating, it has been promoted to increase the coating speed when producing coated paper from the viewpoint of rationalization. There is a need for compositions.

Further, not only the coating speed but also the printing speed on coated paper have been increased, and high-speed printability superior to the conventional one has been demanded.

That is, the paper coating composition is required to have excellent fluidity and mechanical stability during high-speed coating,
Coated paper is required to have excellent print strength, blister resistance, and print gloss.

It is known that the copolymer latex, which is a component of the coating color, has a great influence on these properties.

Further, these copolymer latexes
Odors, often due to alkyl mercaptans, particularly used as chain transfer agents, can be problematic. This odor reduces the commercial value of the final product,
There is a need for a copolymer latex that produces less odor.

[0015]

Means for Solving the Problems The present inventors have conducted intensive studies on the above problems, and as a result, by carrying out emulsion polymerization in the presence of a specific compound, the formation of fine coagulated products was suppressed, A copolymer latex having good stability can be efficiently obtained, and by using the copolymer latex, fluidity and mechanical stability during paper coating are excellent, and the odor of coated paper and the And a paper coating composition having improved printing strength, printing gloss and blister resistance , and a carpet backing adhesive composition having improved adhesion strength, water resistance and odor, and adhesion for rock fiber base material. It has been found that an agent composition can be obtained, and the present invention has been achieved.

That is, the present invention relates to 10 to 80% by weight of an aliphatic conjugated diene monomer, 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer, and 10 to 10% by weight of another monomer copolymerizable therewith. Emulsion polymerization of 89.5% by weight in the presence of a cyclic unsaturated hydrocarbon having one unsaturated bond in a ring selected from cyclopentene, cyclohexene, cycloheptene, 4-methylcyclohexene, and 1-methylcyclohexene. The present invention provides a method for producing a copolymer latex characterized by the following.

Hereinafter, the present invention will be described in detail.

The aliphatic conjugated diene monomer in the present invention includes 1,3-butadiene, 2-methyl-1,3-
Butadiene, 2,3-dimethyl-1,3-butadiene,
Examples thereof include 2-chloro-1,3-butadiene, substituted linear conjugated pentadienes, substituted and side chain conjugated hexadienes, and one or more kinds can be used. In particular, 1,3-butadiene is preferred.

Examples of the ethylenically unsaturated carboxylic acid monomer include mono- or dicarboxylic acids (anhydrides) such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid and itaconic acid.

Other monomers copolymerizable with the aliphatic conjugated diene monomer and the ethylenically unsaturated carboxylic acid monomer include alkenyl aromatic monomers and unsaturated carboxylic acid alkyl ester monomers. And unsaturated monomers containing a hydroxyalkyl group, vinyl cyanide monomers, unsaturated carboxylic acid amide monomers and the like.

The alkenyl aromatic monomers include styrene, α-methylstyrene, methyl α-methylstyrene,
Vinyl toluene and divinyl benzene, and the like,
One or more kinds can be used. Particularly, styrene is preferred.

The unsaturated carboxylic acid alkyl ester monomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, glycidyl methacrylate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl malate, dimethyl dimethyl Examples include itaconate, monomethyl fumarate, monoethyl fumarate, 2-ethylhexyl acrylate, and the like, and one or more kinds can be used. Particularly, methyl methacrylate is preferred.

Examples of unsaturated monomers containing a hydroxyalkyl group include β-hydroxyethyl acrylate and β-hydroxyethyl acrylate.
-Hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate,
Hydroxybutyl acrylate, hydroxybutyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, di- (ethylene glycol) maleate,
Di- (ethylene glycol) itaconate, 2-hydroxyethyl maleate, bis (2-hydroxyethyl)
Maleate, 2-hydroxyethyl methyl fumarate and the like can be mentioned, and one kind or two or more kinds can be used. Particularly, β-hydroxyethyl acrylate is preferable.

Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and α-ethylacrylonitrile.
One or more kinds can be used. Acrylonitrile is particularly preferred.

The unsaturated carboxylic acid amide monomers include:
Acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N,
N-dimethylacrylamide and the like can be mentioned, and one kind or two or more kinds can be used. Acrylamide is particularly preferred.

The above monomer composition comprises 10 to 80% by weight of an aliphatic conjugated diene monomer, 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer, and another monomer copolymerizable therewith. It is 10 to 89.5% by weight of the body.

When the amount of the aliphatic conjugated diene-based monomer is less than 10% by weight, the printing strength and adhesiveness are unfavorably increased. If the amount of the ethylenically unsaturated carboxylic acid monomer is less than 0.5% by weight, mechanical stability is poor, and if it exceeds 10% by weight, the viscosity of the latex tends to increase, which is not preferable. If the amount of the other copolymerizable monomer is less than 10% by weight, water resistance is exceeded, and if it exceeds 89.5% by weight, the printing strength and adhesiveness tend to be poor, which is not preferable.

The chain transfer agent used in the present invention includes:
n-hexyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-stearyl mercaptan and other alkyl mercaptans, xanthogen compounds such as dimethyl xanthogen disulfide, diisopropyl xanthogen disulfide, and α- Methylstyrene dimer, terpinolene, tetramethylthiuram disulfide, tetraethylthiuram disulfide,
Thiuram compounds such as tetramethylthiuram monosulfide, phenol compounds such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol, allyl compounds such as allyl alcohol, dichloromethane, dibromomethane, carbon tetrachloride , Halogenated hydrocarbon compounds such as carbon tetrabromide, vinyl ethers such as α-benzyloxystyrene, α-benzyloxyacrylonitrile, α-benzyloxyacrylamide, triphenylethane, pentaphenylethane, acrolein, methacrolein, α-benzyl Roxystyrene, thioglycolic acid, thiomalic acid, 2-ethylhexylthioglycolate and the like can be mentioned, and one or more kinds can be used.

The amount of the chain transfer agent used is not particularly limited and can be appropriately adjusted depending on the performance required for the copolymer latex. Preferably, the amount is 0.05 to 100 parts by weight based on the monomer mixture. 10 parts by weight.

Most of the cyclic unsaturated hydrocarbon having one unsaturated bond in the ring used in the present invention remains unreacted after the polymerization, and it is necessary to recover the unreacted product. Therefore, those having a boiling point of 140 ° C. or less are preferable.
Specific examples include cyclopentene, cyclohexene, cycloheptene, 4-methylcyclohexene, 1-methylcyclohexene and the like.

The amount of the compound used in the present invention is 0.1 to 30 parts by weight based on 100 parts by weight of the monomer mixture. If the amount is less than 0.1 part by weight, the effect of the present invention is insufficient, and if the amount exceeds 30 parts by weight, the amount of the compound remaining as an unreacted substance also relatively increases, and the energy required for the recovery increases. Not preferred. Preferably 0.5
１５15 parts by weight.

The method of adding various components in the present invention is not particularly limited, and any of a batch addition method, a division addition method, and a continuous addition method can be employed. Further, in the emulsion polymerization, a commonly used emulsifier, polymerization initiator, electrolyte, polymerization accelerator, chelating agent and the like can be used.

In the present invention, one-stage polymerization, two-stage polymerization, multi-stage polymerization and the like can be employed, but emulsion polymerization is particularly preferred by the following method.

That is, in the first stage, 3 to 40% by weight, preferably 5 to 30% by weight of the monomer is polymerized with respect to all the monomers, and the polymerization conversion in the first stage is 50% or more. Preferably, the remaining monomer is added when the content becomes 70% or more, and the polymerization is substantially completed. In the above-mentioned production method, it is particularly preferable to use the ethylenically unsaturated carboxylic acid monomer in the first stage in total amount.

Examples of the emulsifier include anionic salts such as sulfates of higher alcohols, alkylbenzene sulfonates, alkyl diphenyl ether sulfonates, aliphatic sulfonates, aliphatic carboxylates, and sulfate salts of nonionic surfactants. A surfactant or a nonionic surfactant such as an alkyl ester type, an alkyl phenyl ether type or an alkyl ether type of polyethylene glycol is used alone or in combination of two or more.

As the initiator, a water-soluble initiator such as potassium persulfate, ammonium persulfate and sodium persulfate, a redox initiator or an oil-soluble initiator such as benzoyl peroxide can be used.

By adopting the above-mentioned production method, it is possible to suppress the generation of fine coagulated products and to obtain a copolymer latex having good polymerization stability. Since a cyclic unsaturated hydrocarbon having one unsaturated bond is not preferable in terms of working environment hygiene in the final use, in the present invention, after the copolymer latex is polymerized by the production method, an unreacted product is produced. (Substantially 0.5 parts by weight or less, more preferably 0.1 parts by weight or less based on 100 parts by weight of the copolymer latex (solid content)).

Known methods for removing the compound include:
For example, it can be removed by steam distillation, vacuum distillation, or blowing of an inert gas.

Further, the present invention provides various adhesive compositions containing the copolymer latex produced by the above-mentioned method. For example, a composition for paper coating,
It can be used as an adhesive composition for carpet backing, an adhesive composition for rock fiber base materials, an adhesive composition for tire cords, an adhesive composition for wood, an adhesive composition for leather and the like.

The paper coating composition of the present invention is prepared as an aqueous dispersion of the copolymer latex, together with a pigment and, if necessary, other binders.

At this time, the copolymer latex of the present invention is 2 to 100 parts by weight, preferably 5 to 30 parts by weight, and the other binder is 0 to 100 parts by weight of the solid content.
30 parts by weight can be used.

Here, as the pigment, kaolin clay,
Talc, barium sulfate, titanium oxide, calcium carbonate,
Examples thereof include inorganic pigments such as aluminum hydroxide, zinc oxide and satin white, and organic pigments such as polystyrene latex, and these are used alone or in combination.

Other binders include modified starches such as starch, oxidized starch and esterified starch, natural binders such as soybean protein and casein, and synthetic latexes such as polyvinyl alcohol, polyvinyl acetate latex and acrylic latex. Is used.

To prepare the paper coating composition of the present invention,
Furthermore, other auxiliaries, such as dispersants (sodium pyrophosphate, sodium polyacrylate, sodium hexametaphosphate, etc.), defoamers (polyglycols, fatty acid esters, phosphate esters, silicone oils, etc.), leveling agents (funnel oil, Dicyandiamide, urea, etc.),
Preservatives, water resistant agents (formalin, hexamine, melamine resin, urea resin, glyoxal, etc.), release agents (calcium stearate, paraffin emulsion, etc.), fluorescent dyes, color water retention improvers (carboxymethyl cellulose, sodium alginate, etc.) It is added as needed.

The method of applying the paper coating composition of the present invention to coated paper can be performed by a known technique, for example, an air knife coater.
It is performed by a coating machine such as a blade coater, a roll coater, and a bar coater. After the application, the surface is dried and finished with a calender ring or the like.

The carpet backing adhesive composition of the present invention is obtained by blending a filler and / or other additives with the above-mentioned copolymer latex. At this time, the filler is usually 0 based on 100 parts by weight of the copolymer latex in terms of solid content.
Up to 800 parts by weight can be used.

Examples of the filler include calcium carbonate, aluminum hydroxide, hollow glass spheres, clay, talc, silica, carbon black and the like, and these can be used alone or in combination.

Other additives include generally added pH adjusters, emulsifiers, stabilizers, vulcanizing agents, vulcanization accelerators, antioxidants, dispersants, defoamers, preservatives, thickeners. , Colorant,
Cross-linking agents, cross-linking assistants and the like can be mentioned.

In the adhesive composition for a rock fiber base material of the present invention, in addition to the above-mentioned copolymer latex, fillers, emulsifiers, stabilizers, antioxidants, ultraviolet deterioration inhibitors, Vulcanizing agents, vulcanization accelerators, dispersants, defoamers, preservatives, thickeners, coloring agents, crosslinking agents, crosslinking aids, and the like can be added.

[0050]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist. In the examples, parts and percentages indicating percentages are based on weight. The measurement of various physical properties in the examples was based on the following methods.

Dirt of the reactor After the polymerization, the deposits on the inner wall of the reactor were visually observed.

The fine coagulated material of several μm to 50 μm present in the finely coagulated latex is observed with a microscope. ○: very small Δ: small ×: large;

Gel content A latex film is prepared by drying at room temperature. Thereafter, about 1.0 g of the latex film was accurately weighed, put in 400 cc toluene, left to dissolve for 48 hours, filtered through a 300-mesh wire gauze, dried, and the toluene-insoluble matter (gel) on the wire gauze was weighed to calculate the gel content. I do.

Polymerization Example 1 of Copolymer Latex In a 10-liter autoclave, 100 parts of water, 0.3 parts of sodium dodecylbenzenesulfonate, 0.2 parts of sodium hydrogen carbonate, 1.0 part of potassium persulfate and Table 1 were prepared.
Or a first-stage monomer mixture shown in Table 2, a chain transfer agent,
A cyclic unsaturated hydrocarbon having one unsaturated bond in the ring was charged and the first-stage polymerization was performed at 65 ° C. When the conversion of the first-stage emulsion polymerization reached 70%, the second-stage polymerization was performed by continuously adding the monomer mixture, the chain transfer agent, and the unsaturated hydrocarbon in the second-stage for 7 hours. . Thereafter, in order to complete the polymerization, the reaction was continued for another 3 hours to terminate the polymerization. The polymerization conversions were all 98% or more. After adjusting the pH of the obtained copolymer latex to 8 using sodium hydroxide, unreacted monomers and unsaturated hydrocarbons remaining as unreacted substances were removed by steam distillation. ~ 17.

In the table, the left side indicates the weight of the first row and the right side indicates the weight of the second row with "/" interposed therebetween.

Preparation of Paper-Coating Composition Each of the copolymer latexes 1 to 17 was adjusted with pure water so as to have a solid content of 60% based on the following formulation, to obtain a paper-coating composition. Was. The obtained paper coating composition was measured for mechanical stability and fluidity.

(Formulation) Kaolin clay 80 parts Calcium carbonate 20 parts Modified starch 6 parts Copolymer latex 12 parts (solid content)

The composition was coated on a commercially available high-quality paper (64 g / m ² ) using a coating bar such that the coating amount of the composition was 10 g / m ^{2 on} one side, and then dried.
A super calender treatment was performed at 70 ° C. and a linear pressure of 70 to 80 kg / cm 2 to obtain a coated paper. The obtained coated paper was measured for RI Wet Pick, RI Dry Pick, blister resistance, print gloss and odor.

Mechanical Stability The above paper coating composition was kneaded between a metal roll and a rubber roll using a patter -stable tester, subjected to mechanical shearing, and the time (minutes) until a coagulated product was generated on the rubber roll. Measure. ：: 30 minutes or more △: 20 minutes or more and less than 30 minutes ×: less than 20 minutes

The viscosity of the paper coating composition is measured at a rotational speed of 4000 rpm using Bob F with a fluid Hercules high-shear viscometer. The lower the viscosity, the better the fluidity.

RI Wet Pick The degree of picking when printing with a fountain solution using a RI printing machine is visually judged, and five grades from first grade (best) to fifth grade (worst). It was evaluated by the method. The average value of 6 times is shown.

The evaluation was performed in the same manner as in the above-mentioned RI Wet Pick except that the RI Dry Pick fountain solution was not used.

Blister resistance The minimum temperature at which blistering occurs when the double-sided printing coated paper is humidified (about 6%) and thrown into a heated oil bath.

Printing A constant-speed printing is performed using a glossy RI printing machine and a commercially available red ink for offset printing to prepare a sample. The gloss of the printed surface of the sample is measured according to the method of JIS P-8142. The higher the value, the better the gloss.

A coated paper was obtained in the same manner as described above, except that the amount of the odor paper coating composition applied was 20 g / m ² per side. A test piece of 10 cm × 10 cm was prepared from the obtained coated paper, and three test pieces were placed in a glass bottle capable of being sealed. After leaving at 50 ° C. for 1 hour, the stopper was removed to determine the degree of odor. did. ×: Smell △: Smell slightly ○: Almost no smell

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

[Table 3]

Polymerization Example 2 of Copolymer Latex In a 10-liter autoclave, 100 parts of water, 0.6 parts of sodium dodecylbenzenesulfonate, 0.3 parts of sodium hydrogen carbonate, 0.8 parts of potassium persulfate and shown in Table 4 A first-stage monomer mixture, a chain transfer agent, and a cyclic unsaturated hydrocarbon having one unsaturated bond in the ring are charged and the mixture is charged at 60 ° C.
To carry out the first-stage polymerization. When the conversion of the first stage reached 75%, the monomer mixture of the second stage, the chain transfer agent, and the unsaturated hydrocarbon were continuously added over 6 hours, and the second stage of polymerization was carried out at 70 ° C. Thereafter, in order to complete the polymerization, the reaction was continued for another 3 hours to terminate the polymerization. All polymerization conversion rates are 9
8% or more. After adjusting the pH of the obtained copolymer latex to 8 using sodium hydroxide, unreacted monomers and unsaturated hydrocarbons remaining as unreacted substances are removed by steam distillation. ~ 26 was obtained.

Preparation of Adhesive Composition for Carpet Backing Copolymer latexes 18 to 26 were each adjusted to pH 8.5 with an aqueous sodium hydroxide solution. To 100 parts (solid content) of each of the latexes whose pH was adjusted, 1.0 part of Aron T-40 (manufactured by Toagosei Co., Ltd .: low molecular weight sodium polyacrylate) and 400 parts of heavy calcium carbonate were used as dispersants. In addition, Alon A-20P (manufactured by Toagosei Co., Ltd .: high molecular weight sodium polyacrylate) as a thickener
1.0 part was added, and the solid content was reduced to 7 with ion exchanged water.
It was adjusted to 5% by weight to obtain an adhesive composition for carpet backing having a viscosity of 17000 to 20,000 centipoise (BM type viscometer, 12 rpm, # 4 rotor, 20 ° C).

The resulting adhesive composition was uniformly applied to the back of a tufted carpet greige having a base cloth of polypropylene split yarn and a pile of 6 nylon of 1/8 inch gauge at an apparent weight of 1200 g / m ² . A 7 oz./square yard jute woven backing is applied over it,
Drying at 0 ° C. for 20 minutes gave a carpet lined with jute.

Using these carpets, the adhesive strength was measured in accordance with JIS10211. Next, the carpet made in the same manner was immersed in ion exchanged water at 20 ° C. for 1 hour.
The adhesive strength was measured according to JIS10211. Also, 10cm
A test piece of × 10 cm was prepared, placed in a glass bottle capable of being sealed, left at 50 ° C. for 1 hour, and the stopper was removed to determine the degree of odor. ：: Almost no odor Δ: Slightly odor X: Smell The results are shown in Table 5.

[0073]

[Table 4]

[0074]

[Table 5]

Polymerization Example 2 of Copolymer Latex In a 20-liter autoclave, 100 parts of water, 0.8 parts of sodium dodecylbenzenesulfonate, 0.3 parts of sodium hydrogen carbonate, 0.9 parts of potassium persulfate and 1 part shown in Table 6 The monomer mixture of the second stage, a chain transfer agent, and a cyclic unsaturated hydrocarbon having one unsaturated bond in the ring were charged.
The first-stage polymerization was performed at 5 ° C. 80% first stage conversion
, The second-stage monomer mixture, chain transfer agent,
Unsaturated hydrocarbons were continuously added in 8 hours, and second stage polymerization was performed. Thereafter, the reaction was continued for another 3 hours to complete the polymerization, and the polymerization was terminated. All polymerization conversion rates are 98%
That was all. After adjusting the pH of the obtained copolymer latex to 8 with sodium hydroxide, unreacted monomers and unsaturated hydrocarbons remaining as unreacted substances are removed by steam distillation, and the copolymer latexes 27 to 34 are removed. Obtained.

Preparation of adhesive composition for rock fiber base material Copolymer latex 27-34 100 parts each (solid content)
, 2 parts of zinc white, 1 part of zinc dibutyldithiocarbamate and 1 part of antigen S (styrenated phenol: manufactured by Sumitomo Chemical Co., Ltd.) were added, and 0.3 part of carboxymethylcellulose was added as a thickener. The solid content was adjusted to 48.0% by weight, and the viscosity was 1000 to 13%.
00 centipoise (BM type viscometer, 60 rpm, #
(3 rotors, 20 ° C.) to prepare an adhesive composition for rock fiber substrates.

These adhesive compositions were adjusted to a solid content of 40.0% by weight with ion-exchanged water, and were 100 mm long, 100 mm wide,
About 2 g of palm rock fiber having a thickness of 20 mm and a weight of 3.0 g was spray-coated on the surface, and dried at 80 ° C. for 10 minutes.
Further, the back surface was similarly spray-coated and dried at 80 ° C. for 10 minutes. After that, heat at 130 ° C for 15 minutes,
Crosslinking was promoted to produce a lock test piece.

Using these test pieces, tests of adhesive strength and water-resistant adhesive strength were performed. Table 6 shows the results.

Adhesive strength: Measured with an Instron tensile tester.

Adhesion strength after immersion: Each lock test piece was heated at 20 ° C.
After the sample was immersed in ion-exchanged water, measured by an Instron tensile tester.

[0081]

[Table 6]

Claims (2)

(57) [Claims] 1. An aliphatic conjugated diene-based monomer and another monomer copolymerizable therewith, comprising cyclopentene, cyclohexene, cycloheptene, 4-methylcyclohexene,
A process for producing a copolymer latex, which comprises carrying out emulsion polymerization in the presence of a cyclic unsaturated hydrocarbon having one unsaturated bond in a ring selected from 1-methylcyclohexene. 2. An aliphatic conjugated diene monomer in an amount of 10 to 80% by weight and an ethylenically unsaturated carboxylic acid monomer in an amount of 0.5 to 10%.
% By weight and other monomers copolymerizable therewith.
The method for producing a copolymer latex according to claim 1, wherein a monomer mixture comprising 9.5% by weight is used.