JPS6250487B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an aqueous dispersion of vinyl chloride/vinyl ester/ethylene copolymer with improved thermal fluidity. More specifically, in producing an aqueous copolymer dispersion consisting of vinyl chloride, vinyl ester and ethylene,
In the presence of an emulsifying dispersant and a radical polymerization initiator and under pressure of ethylene, (1) 0.1 to 1.0% by weight of the general formula [] based on the total amount of vinyl chloride and vinyl ester to be subjected to copolymerization. (In the formula, X ₁ , X ₂ , X ₃ , and X ₄ are −COOCH ₂ CH=
CH ₂ or either one represents an H atom. ) is dissolved in vinyl ester and/or vinyl chloride and continuously added to the polymerization system (2) and based on the total amount of vinyl chloride and vinyl ester to be subjected to copolymerization. 20-75% by weight of vinyl chloride, 15-70% by weight of vinyl ester, characterized in that 60% by weight or more thereof is continuously added to the polymerization system.
an aqueous dispersion of a copolymer consisting of vinyl chloride, vinyl ester and ethylene, having a composition of 5-30% by weight and ethylene, and an insoluble content of 5-60% by weight in benzene as a solvent. This invention relates to a method for producing a liquid. Conventionally, aqueous copolymer dispersions of vinyl esters and ethylene, typified by vinyl chloride and vinyl acetate, have excellent water resistance and alkali resistance, and can be used in a wide range of applications such as adhesives, paints, fibers, and paper processing. Are known. However, such vinyl chloride/vinyl ester/
In an aqueous dispersion of ethylene copolymer, the amount of vinyl chloride copolymerized in vinyl chloride/vinyl ester/ethylene copolymer is increased with the intention of imparting the water resistance, flame retardance, and chemical resistance characteristics of vinyl chloride. In this case, the molecular weight of the copolymer decreases,
The disadvantage is that the thermal fluidity increases. For example, when a vinyl chloride/vinyl ester/ethylene copolymer aqueous dispersion is used as an adhesive for a thermoplastic resin and the thermoplastic resin is embossed, when the product undergoes thermal history, the embossing mold A problem arises in that it tends to collapse. Furthermore, when used as a vehicle for a paint, if the molecular weight is low, the strength of the paint film will be poor, and for example, the paint film will have the drawback of lacking strength in wash resistance.
Alternatively, when used as a binder for fibers, if the molecular weight is low, the polymer has thermal fluidity, which may cause problems in heat resistance stability. The present invention provides such vinyl chloride/vinyl ester/
Various studies were conducted to improve the thermal fluidity and strength of ethylene copolymers when the vinyl chloride content is high, without sacrificing the basic features of the copolymers. As a result, in emulsion polymerization under ethylene pressure, 0.1 to 1.0% by weight of the above [] based on the total amount of vinyl chloride and vinyl ester to be subjected to copolymerization.
Polybasic acid polyallylic ester represented by the formula is dissolved in vinyl chloride and/or vinyl ester to be subjected to copolymerization, and continuously added to the polymerization system, and It has been found that an aqueous copolymer dispersion prepared by a method in which 60% by weight or more of the total amount is continuously added to the polymerization system during polymerization has significantly improved thermal fluidity and strength. Generally, a polyfunctional monomer having two or more polymerizable double bonds in the molecule is introduced into a polymer or copolymer to increase the molecular weight of the polymer or copolymer or to cause cross-linking. It is known to produce gels that are insoluble in organic solvents by. For example, in Japanese Patent Publication No. 52-37012, solvent resistance,
For the purpose of improving mechanical properties at high temperatures, an aqueous vinyl acetate/ethylene copolymer dispersion using a polybasic acid vinyl ester or a polyfunctional acid allyl ester as a cross-linking agent has been disclosed. Special Public Service 1977-
No. 19179 discloses that in an aqueous dispersion of vinyl chloride/vinyl acetate/ethylene copolymer with a vinyl chloride content of 35% by weight or less, divinyl succinate or glycol dimethacrylate is added to 1% of the total monomers.
It is stated that when used in proportions up to %, the molecular weight is increased or cross-links are created. In addition, Tokuko No. 42-9671 has low thermal deformability,
In addition, when producing a vinyl chloride polymer with a high degree of polymerization and good processability, it has been said that when dibasic acid diallyl esters are used with saturated hydrocarbon diol divinyl ethers, a large amount of gel insoluble in organic solvents is generated. However, it is possible to produce vinyl chloride polymers with a high average degree of polymerization. Furthermore, in Japanese Patent Publication No. 49-32787, unsaturated carboxylic acid is added as an unsaturated compound that can participate in copolymerization in an aqueous dispersion of a copolymer of olefin, vinyl halide, vinyl ester/and alkyl acrylate or alkyl methacrylate. Examples include acids, acrylonitrile, nitrogen-containing unsaturated compounds, allyl compounds such as diallyl phthalate, and divinyl compounds such as divinylbenzene. However, all polyfunctional monomers that have two or more polymerizable double bonds in their molecules increase the molecular weight of the polymer or copolymer, or cause cross-linking to reduce insolubility in organic solvents. However, even if the purpose is achieved, it may not be possible to obtain a stable aqueous dispersion. It is necessary to carefully consider the selection of polyfunctional monomers suitable for the purpose of modification and the method for using them. In this technical background, in order to improve the thermal fluidity and strength of the vinyl chloride/vinyl ester/ethylene copolymer composition that is the object of the present invention, the compound of the formula [] is combined with vinyl chloride and vinyl ester. 0.1 to 1.0% by weight based on the total amount of the compound, and this method of use has been achieved for the first time under the conditions specified in the present invention. For example, when triallyl cyanurate used in the example of Japanese Patent Publication No. 52-37012 is used instead of the polybasic acid polyallyl ester of the present invention,
Although the desired amount of benzene-insoluble content can be achieved within the range of the amount used in the present invention, the resulting aqueous dispersion of the copolymer has many coarse particles and is unstable, with a large amount of sediment forming during storage. It was an aqueous dispersion with poor properties. Furthermore, glycol dimethacrylate or glycol diacrylate described in Japanese Patent Publication No. 46-19179, octadecanediol divinyl ether described in Examples of Japanese Patent Publication No. 42-9671, or triacrylate or trimethacrylate of trifunctional monomers. When the compound is used, within the range of the polybasic acid polyallyl ester used according to the present invention, not only benzene insoluble matter but also no increase in molecular weight is observed, and vinyl chloride/vinyl ester/vinyl ester/
The objective of improving the physical properties of ethylene copolymers was not achieved. Furthermore, Japanese Patent Publication No. 49-32789 does not contain any information regarding the selection and use of polyfunctional monomers to achieve the objectives of the present invention.
The description merely indicates the scope of the contents of the publicly known documents exemplified above. Polybasic acid polyallyl esters represented by the formula [ ] used in the present invention include, for example, triallyl ester of benzenetricarboxylic acid, tetraallyl ester of benzenetetracarboxylic acid, and the like. The amount of polybasic acid polyallyl ester used in the present invention is 0.1 to 1.0% by weight, preferably 0.2 to 0.8% by weight, based on the total amount of vinyl chloride and vinyl ester to be subjected to emulsion copolymerization. Within this range of usage, a benzene-insoluble content of 5 to 60% by weight, preferably 10 to 50% by weight, can be produced in the vinyl chloride/vinyl ester/ethylene copolymer having the composition of the present invention. In the present invention, if the amount of polybasic acid polyallyl ester used is less than 0.1% by weight, a copolymer having a benzene insoluble content of more than 5% by weight cannot be obtained, and the physical properties of the copolymer, such as thermal fluidity and strength, cannot be obtained. The purpose of improvement is not fully achieved. Also,
If the amount used is more than 1.0% by weight, the copolymer will have a benzene-insoluble content of more than 60% by weight, and a stable aqueous dispersion cannot be obtained by the method of the present invention. Furthermore, in the present invention, when producing an aqueous dispersion of vinyl chloride/vinyl ester/ethylene copolymer using polybasic acid polyallylic ester as described above, 60% by weight or more of the vinyl chloride and vinyl ester to be subjected to polymerization is It is necessary to continuously add the polybasic acid polyallylic ester to the polymerization system during the polymerization, and to dissolve the polybasic acid polyallyl ester in vinyl chloride and/or vinyl ester and continuously add it to the polymerization system during the polymerization. By this method, a copolymer having a uniform composition and benzene-insoluble content and a stable aqueous dispersion can be obtained. For example, polybasic acid polyallylic esters may be added in their entirety to the polymerization system before the start of polymerization, or may be added unevenly during polymerization, or may be added without being dissolved in vinyl chloride and/or vinyl esters. Not only is the amount of benzene insoluble in the polymer not reproducible, but many coarse particles are produced, resulting in an aqueous dispersion with poor stability. In addition, if more monomers than 40% by weight of the total amount of vinyl chloride and vinyl ester to be subjected to polymerization are supplied to the polymerization system before the start of polymerization, the composition of the copolymer formed in the early stage of polymerization after the start of polymerization The composition of the copolymer produced in the late stage of polymerization differs greatly. Furthermore, in this case, even if the polybasic acid polyallyl ester is added all at once before the start of polymerization, or even if it is dissolved in the monomer added during polymerization, many coarse particles are likely to be produced, resulting in an aqueous dispersion with poor stability. A preferred method of the present invention will be explained in more detail. That is, first, less than 40% by weight of the total amount of vinyl chloride and vinyl acetate to be subjected to copolymerization is charged into the polymerization reaction system, polymerization is started, and the remaining monomers, which are 60% by weight or more, are subjected to the polymerization reaction. The process is continued under pressure of ethylene so as to be charged into the polymerization system as uniformly as possible, and in this case, the polybasic acid polyallyl ester is dissolved in the vinyl chloride and/or vinyl ester charged during the above polymerization reaction and polymerized. It is preferable to subject it to. Alternatively, it is preferable to use a method in which a polybasic acid polyallylic ester is uniformly dissolved in the entire amount of vinyl chloride or vinyl ester to be subjected to copolymerization, and then subjected to polymerization. Examples of the vinyl ester in the present invention include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl laurate, and vinyl tertiary carboxylate. Preferred is vinyl acetate, and a mixture of vinyl acetate and the above-mentioned vinyl esters can be used. As the radical polymerization initiator in the present invention,
Radical polymerization initiators generally used in emulsion polymerization can be used, but particularly preferred radical polymerization initiators include so-called redox catalysts consisting of an oxidizing agent and a reducing agent. As the oxidizing agent, for example,
These include hydrogen peroxide, persulfates such as ammonium persulfate, and potassium persulfate, and perborates. Examples of reducing agents include l-ascorbic acid, sodium bisulfite, Rongarit, glyoxal sodium bisulfite, and ferrous sulfate. As the emulsifying dispersant in the present invention, various water-soluble polymers are used as protective colloids, or various nonionic surfactants or anionic surfactants are used as emulsifiers, and these are used alone or in combination. Examples of these protective colloids include polyvinyl alcohol, partially saponified polyvinyl alcohol, fibrous derivatives such as methyl cellulose, and hydroxyethyl cellulose. Examples of nonionic surfactants include polyoxyethylene alkyl ethers and polyoxyethylene alkyl phenol ethers such as polyoxyethylene lauryl ether, polyoxyethylene octyl phenol ether, polyoxyethylene nonyl phenol ether, and polyoxyethylene sorbitan monomer. Examples include polyoxyethylene sorbitan resin acid esters such as laurate, polyoxyethylene sorbitan monooleate, and polyoxyethylene polyoxypropylene block copolymers with an added amount of ethylene oxide of 10 to 80%. Examples of anionic emulsifiers include lauryl sulfate, etc. Higher alcohol sulfate ester salts such as ester soda salts, polyoxyethylene alkyl sulfate soda salts, polyoxyethylene sulfate salts such as polyoxyethylene alkyl phenisulfate sodium salts, and sodium dialkyl sulfosuccinates. Examples include dialkyl sulfosuccinates, alkylbenzene sulfonates, and the like. In addition, in emulsion polymerization, aqueous dispersions are
It is preferable to polymerize while maintaining the pH at 3 to 7 using a mm ² regulator. Examples of the PH adjuster include ammonium bicarbonate, sodium bicarbonate, disodium phosphate, sodium pyrophosphate, sodium acetate, aqueous ammonia, acetic acid, and hydrochloric acid, which may be used alone or in combination of two or more. . The appropriate polymerization temperature in the present invention is 30 to 70°C, and when the ethylene content of the copolymer of the present invention is 5 to 30% by weight, the polymerization pressure is 15 to 150 kg/kg.
An ethylene pressure of cm ² is used. In addition, the production method of the present invention involves a so-called reaction in which the vinyl chloride/vinyl ester/ethylene copolymer is further copolymerized with a vinyl monomer containing 10% by weight or less of a functional group based on vinyl chloride, vinyl ester, and ethylene. It can also be applied to the production of vinyl chloride/vinyl ester/ethylene copolymer aqueous dispersions. Examples of the vinyl monomer containing a functional group include vinyl monomers having a glycidyl group such as glycidyl acrylate and grindyl methacrylate, vinyl monomers having an N-methylol group such as N-methylolacrylamide and N-methylolmethacrylamide, Also, vinyl monomers having an alkoxymethyl group in which the N-methylol group is replaced with an alkyl ether such as ethyl or butyl ether, vinyl monomers having a carboxyl group such as acrylic acid, itaconic acid, and maleic acid,
Vinyl monomers having a hydroxyalkyl group such as 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate are exemplified. One or more of these vinyl monomers can be used in an amount of 10% by weight or less based on the vinyl chloride/vinyl ester/ethylene copolymer, which is within a range that does not impair polymerization. Even when using functional vinyl monomers having these glycidyl groups, N-methylol groups, alkoxymethyl groups, carboxylic acids, and hydroxyalkyl groups, vinyl chloride or acetic acid can be prepared in the same manner as the polybasic acid polyallyl ester described above. Most preferably, it is subjected to copolymerization by mixing it with vinyl and subjecting it to the polymerization reaction, or, if it is a water-soluble vinyl monomer, by adding it continuously to the polymerization reaction system as an aqueous solution during polymerization. This will be explained below using examples. Example 1 The following items were charged into a pressure reactor. 12800 g Water 120 g Hydroxyethyl cellulose 130 g Polyoxyethylene lauryl ether 130 g Polyoxyethylene nonyl phenol ether 60 g Sodium lauryl sulfate 7 g Acetic acid 8 g Sodium acetate 0.3 g FeSO ₄ 90 g Rongalit 1726 g Vinyl acetate Next, after purging the reactor with nitrogen and ethylene, chlorination 1643 g of vinyl was charged, ethylene was added, the pressure was raised to 60 kg/cm ² , and 8% by weight ammonium persulfate aqueous solution was added to initiate polymerization. The polymerization temperature was adjusted to 50°C. Next, 4225 g of vinyl chloride, 4436 g of vinyl acetate and 1.
A mixed monomer mixture of 40.6 g of 2,4-benzenetricarboxylic acid triallyl ester was added at a constant rate over a period of 5 hours. When unreacted vinyl acetate decreased to 0.3% after a polymerization time of 7 hours, the reactor was cooled and unreacted ethylene was discharged. The solid content of the obtained vinyl chloride/vinyl acetate/ethylene copolymer aqueous dispersion was 51% by weight, and the amount of coarse particles that could not be filtered through a 100-mesh wire mesh was 15 ppm, and it was a stable aqueous dispersion that did not produce sediment during standing. It was a dispersion liquid. The composition of the copolymer was 40% by weight vinyl chloride, 42% by weight vinyl acetate, and 18% by weight ethylene. Furthermore, the benzene-insoluble content of the copolymer was 28% by weight. Example 2 The following items were charged into a pressure reactor. 12800g Water 120g Hydroxyethyl cellulose 150g Polyoxyethylene lauryl ether 160g Polyoxyethylene nonyl phenol ether 7g Acetic acid 8g Sodium acetate 0.3g FeSO ₄ 90g Rongarit 1095g Vinyl acetate Next, after purging the reactor with nitrogen and ethylene, add 2346g of vinyl chloride. , add ethylene to make the pressure 45Kg/cm ² , add 8% by weight ammonium persulfate aqueous solution to start polymerization, and set the polymerization temperature to 50℃.
I adjusted it so that Next, a mixed monomer mixture of 5474 g of vinyl chloride, 2554 g of vinyl acetate, and 60 g of 1,2,4-benzenetricarboxylic acid triallyl ester, and an aqueous solution of 250 g of N-methylolacrylamide dissolved in 1000 g of water were fed at a constant rate for 5 hours from each of the two supply ports. Delivered at speed. When unreacted vinyl acetate decreased to 0.3% after a polymerization time of 6.5 hours, the reactor was cooled and unreacted ethylene was discharged. Obtained vinyl chloride/vinyl acetate/ethylene/
The solid content of the aqueous dispersion of the copolymer of N-methylolacrylamide was 51.2% by weight, and the amount of coarse particles that could not be filtered through a 100-mesh wire mesh was 100 ppm, and it was a stable aqueous dispersion that did not produce sediment during standing. Ta. The composition of the copolymer was 60% by weight vinyl chloride, 28% by weight vinyl acetate, 10% by weight ethylene and 2% by weight N-methylolacrylamide. Furthermore, the benzene-insoluble content of the copolymer was 50% by weight. Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that 1,2,4-benzenetricarboxylic acid triallyl ester was removed. The resulting copolymer dispersion was a stable aqueous dispersion with few coarse particles as in Example 1, but the benzene-insoluble content of the copolymer was 0.6% by weight. Comparative Example 2 Polymerization was carried out in the same manner as in Example 2 except that 1,2,4-benzenetricarboxylic acid triallyl ester was removed. The resulting copolymer dispersion was a stable aqueous dispersion with few coarse particles as in Example 2, but the benzene insoluble content of the copolymer was 1.6% by weight. Comparative Example 3 Polymerization was carried out in the same manner as in Example 1, except that the same amount of triallyl cyanurate was used in place of 1,2,4-benzenetricarboxylic acid triallyl ester. The obtained copolymer had a benzene insoluble content of 16.8% by weight, but the aqueous dispersion had a benzene insoluble content of 16.8% by weight.
The aqueous dispersion contained a large amount of coarse particles of approximately 2000 ppm, which could not be filtered through a 100-mesh gold steel, and had poor stability due to the generation of sediment. Comparative Examples 4 to 12 Polymerization was carried out in the same manner as in Example 1, except that the polyfunctional monomer shown in Table 1 was used instead of 1,2,4-benzenetricarboxylic acid triallyl ester. As shown in Table 1, the aqueous dispersions of the copolymers of Comparative Examples 4 to 12 had no significant difference from Comparative Example 1 in the benzene-insoluble components of the copolymers. Comparative Example 13 In Example 1, when the entire amount of vinyl chloride, vinyl acetate and 1,2,4-benzenetricarboxylic acid triallyl ester was charged before polymerization and polymerization was carried out, the polymerization pressure increased abnormally during the polymerization.
Furthermore, the aqueous dispersion produced contained many coarse particles and was difficult to filter. Comparative Example 14 1726g charged before starting polymerization in Example 1
Polymerization was carried out in the same manner as in Example 1, except that 40.6 g of 1,2,4-benzenetricarboxylic acid triallyl ester was dissolved in vinyl acetate and added before the start of polymerization. The benzene insoluble content of the obtained copolymer is 10
% by weight, but the resulting aqueous dispersion was difficult to filter and had poor stability as sediment was generated during standing. The benzene-insoluble content of the copolymers of Examples and Comparative Examples was determined by dissolving 1 g of the copolymer in 100 g of benzene at 70°C for 3 hours, then filtering it through a 300-mesh wire mesh, and measuring the amount of copolymer that could not be filtered. Ta. Reference Example 1 FIG. 1 shows the flow curves of the copolymers of Examples 1 and 2 and Comparative Examples 1 and 2 measured using a Koka type flow tester (Shimadzu Corporation, Model 301). The measurement conditions were a die diameter of 1 mm, mouth length of 2 mm, 10 minutes of preheating, additional pressure of 10 Kg/cm ² , and a rising rate of 6°C/cm.
Measurements were carried out from 80°C in minutes. As shown in Figure 1, the fluidity of the copolymers of Examples 1 and 2, which have a benzene-insoluble content, is higher than that of the copolymers of Comparative Examples 1 and 2, which have a small amount of benzene-insoluble content, from a relatively low temperature. It shows great fluidity, which is significantly improved. Further, the flow curves of the copolymers of Comparative Examples 4 to 12 are shown in FIG. 1, and the copolymers exhibited almost the same flowability as Comparative Example 1. Reference Example 2 Using the aqueous copolymer dispersions of Example 1 and Comparative Examples 1 and 4, synthetic resin emulsion paints with a pigment volume concentration of 40% were prepared using the paint formulations shown below. Paint formulation (parts: parts by weight) Natrosol 250HR, 2% aqueous solution (hydroxyethyl cellulose) 225 parts Nopco NDW (antifoaming agent) 3 parts Tamol 850 (sodium salt of carboxylated anionic surfactant) 6 parts Emulgen 911 (Polyoxyethylene nonylphenol ether) 4 parts Monin emulsion 2 parts Texanol 10 parts Ethylene glycol 25 parts Titanium dioxide 150 parts Calcium carbonate 150 parts Kaolin clay 50 parts Water 115 parts Aqueous dispersion of copolymer 360 parts (solid content 55 Weight %) The wash resistance of the paint films of these paints was tested in accordance with JISK5663 for synthetic resin emulsion paints. However, 0.5% should be poured onto the surface to be rubbed.
Instead of soapy water, a 2% aqueous solution of polishing sand (a commercially available cleanser for cleaning) was used as an accelerated test under more severe conditions. The test results are shown in Table 2, and Example 1 of the present invention
Synthetic resin emulsion paints using this method exhibited excellent wash resistance and excellent film strength. Reference Example 3 The aqueous copolymer dispersion of Example 3 and Comparative Example 2 was applied to a soft vinyl chloride resin sheet with a thickness of 0.2 mm.
Coated at a rate of 15g/m ² (solid content equivalent) and heated at 130℃
Dry undercoat for 3 minutes, and roll temperature 180℃ on the PVC resin sheet side together with the base fabric (cotton thick Aya 9A).
The embossed vinyl chloride leather was bonded and embossed through an embossing roll. The embossed pattern of the vinyl chloride leather manufactured using Example 2 as an adhesive was clearly visible, but the embossed pattern of the vinyl chloride leather manufactured using Comparative Example 2 was not clearly visible. I felt sore. In addition, each of the above vinyl chloride leathers is 2.5cm wide.
Table 3 shows the results of measuring the peel strength in the 180° direction using an autograph under normal conditions and during heat-resistant treatment (left at 100°C for 24 hours). As shown in Table 3, the vinyl chloride leather using Comparative Example 2 as an adhesive is inferior to the vinyl chloride leather using Example 2 as an adhesive, in terms of strength under normal conditions, especially during heat treatment. It was hot.

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【table】 [Brief explanation of the drawing]

The vertical axis is the amount of plunger drop (15x magnification, mm)
The horizontal axis shows temperature (°C). The curves show the flow curves of the respective copolymers of Comparative Examples 1 and 4 to 12, the curves of Comparative Example 2, the curves of Example 1, and the curves of Example 2.

Claims (1)

[Claims] 1. In producing an aqueous copolymer dispersion comprising vinyl chloride, vinyl ester and ethylene, in the presence of an emulsifying dispersant and a radical polymerization initiator,
Under pressure of ethylene, (1) 0.1 to 1.0% by weight of the polybasic acid polyallyl ester represented by the following general formula [] based on the total amount of vinyl chloride and vinyl ester to be subjected to copolymerization is converted into vinyl ester and/or chloride. It is characterized in that it is dissolved in vinyl and continuously added to the polymerization system (2), and 60% by weight or more of the total amount of vinyl chloride and vinyl ester to be subjected to copolymerization is continuously added to the polymerization system. Vinyl chloride 20-75% by weight, vinyl ester 15-70%
% by weight, and ethylene from 5 to 30% by weight, and with respect to benzene as solvent.
A method for producing an aqueous dispersion of a copolymer consisting of vinyl chloride, vinyl ester and ethylene having an insoluble content of 60% by weight. (In the formula, X ₁ , X ₂ , X ₃ , and X ₄ are −COOCH ₂ CH=
CH ₂ or any one of them represents an H atom. )