JPH0374416A - Water dispersible resin composition for nonwoven fabric or paper impregnation - Google Patents

Abstract

PURPOSE:To obtain the title composition having a low glass transition point and excellent flexibility, strength, water resistance, alkali resistance, etc., by subjecting styrene to emulsion polymerization with an alkyl (meth)acrylate in the presence of a specific unsaturated monomer. CONSTITUTION:Styrene is subjected to emulsion polymerization with a (ment) acrylic acid alkyl ester [preferably ethyl (meth)acrylate] in the presence of 0.2-10wt.% unsaturated glycidyl compound (preferably N-methylolacrylamide) and 0.2-10wt.% unsaturated dicarboxylic acid (preferably itaconic acid) to provide the aimed composition having 10-40 deg.C glass transition point and suitable to a binder for nonwoven fabric or paper used in waterproofing application of architectural structure such as roof, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a water-dispersible resin composition for impregnation, which is suitable as a binder for nonwoven fabrics or papers used in construction. More specifically, a water-dispersible resin composition that imparts excellent normal tensile strength, tear tensile strength, hot tensile strength, water resistance, alkali resistance, flexibility, etc. to asphalt-impregnated nonwoven fabrics used for waterproofing buildings such as roofs and bathrooms. Regarding.

[Conventional technology]

Currently, polyester nonwoven fabrics are widely used as asphalt-impregnated nonwoven fabrics for waterproofing roofs, bathrooms, etc. During the asphalt impregnation process, various water-dispersible resin compositions are simultaneously impregnated as binders for the nonwoven fabrics, and the nonwoven fabrics are coated with waterproof seals.
normal tensile strength, tear tensile strength, hot tensile strength, water resistance and
It is common practice to impart alkali resistance and flexibility. However, the current situation is that these conventional water-dispersible resin compositions do not have sufficient normal tensile strength, tear tensile strength, hot tensile strength, water resistance/alkali resistance, and flexibility imparting effect as nonwoven fabric binders.

As a solution to this problem, a method has been proposed in which a partially methylated methylolmelamine resin is used as a binder in combination with a conventional water-dispersible resin composition (Textile Processing Technology, Textile Machinery Society of Japan, September 25, 1972). Published by Usu, see page 800),
Even so, it was still insufficient to simultaneously satisfy these physical properties.

For example, in Japanese Patent Publication No. 80-44421, a nonwoven fabric binder is obtained by using a water-dispersible resin composition using a hydrophobic unsaturated monomer in combination with a melamine resin. Although it had excellent water resistance and alkali resistance, it did not have heat resistance.

In addition, JP-A-83-270850 describes a nonwoven fabric binder that has a crosslinked structure between and within particles, has strong mechanical strength, and has excellent water resistance and solvent resistance. It is obtained by emulsion polymerization of acrylic ester containing an unsaturated monomer having a group, and has a relatively low glass transition point (hereinafter referred to as Tg) of 10°C to 40°C. The binder does not have strong tensile strength when heated.

[Problem to be solved by the invention]

The present invention overcomes the drawbacks of the prior art, and provides water dispersibility suitable for impregnating nonwoven fabric or paper as an excellent binder that has normal tensile strength, tear tensile strength, hot tensile strength, water resistance, alkali resistance, and flexibility. The present invention aims to provide a resin composition.

[Means to solve the problem]

In order to solve the above problem, the present inventors have conducted intensive research and found that styrene and (meth)acrylic acid alkyl ester are combined with 0.00% of each of an unsaturated glycidyl compound, an unsaturated methylol compound, and an unsaturated dicarboxylic acid. Styrene (obtained by emulsion polymerization in the presence of 2 to 10% by weight)
The water-dispersible resin composition is composed of a water-dispersible resin composition of a meth)acrylic acid alkyl ester copolymer, and the copolymer has a glass transition point of 10 to 40°C, and has a normal tensile strength, a tear tensile strength, It was discovered that the tensile strength under heat, water resistance, alkali resistance, and flexibility are extremely excellent, leading to the present invention.

[For production]

In the present invention, the polymer contains styrene, which imparts tensile strength and water/alkali resistance, and in addition, (meth)acrylic acid esters are used in combination to freely set the Tg, and particles of the water-dispersible resin composition are formed by emulsion polymerization. A water-dispersible resin composition was obtained which had a lipophilic functional group such as a glycidyl group therein and a hydrophilic functional group such as a methylol group present on the particle surface.

The water-dispersible resin composition achieved tough and flexible film characteristics by completing intraparticle and interparticle crosslinking through drying and heat treatment.

In addition, there is a known technique that uses a water-dispersible resin composition and a melamine resin together as a nonwoven fabric binder to impart normal tensile strength and hot tensile strength to the nonwoven fabric, but this technique lacks flexibility and has poor tear tensile strength. was.

As a result of intensive efforts by the present inventors regarding this point, the above-mentioned water-dispersible resin composition has succeeded in imparting the characteristic of having a crosslinked structure both within the particles and between the particles.

That is, the water-dispersible resin composition according to the present invention is strong because it is crosslinked within the particles and between the particles by a condensation reaction between the crosslinkable functional group of the unsaturated monomer and the unsaturated dicarboxylic acid as described above. It provides nonwoven fabric with excellent mechanical strength, tensile strength at high temperatures, and water and alkali resistance.

Furthermore, the second feature of the present invention is that the Tg of the polymer
By setting the temperature at a relatively low temperature of 10° C. to 40° C., in addition to the above-mentioned physical properties, the nonwoven fabric is provided with flexibility and strong tear tensile strength.

In addition, the third feature of the present invention is that the carboxylic acid present in the particles of the water-dispersible resin composition not only crosslinks with the hydrophilic functional groups on the particle surface, but also partially methylated methylolmelamine, which is used as a crosslinking agent by post-addition. It also contributes to crosslinking with the resin.

That is, although the water-dispersible resin composition used in the present invention has a crosslinked structure, it forms a flexible film due to the relatively low Tg polymer as described above. Therefore, while being flexible, it is possible to impart strong tensile strength, hot tensile strength, water resistance, alkali resistance, and flexibility functions to the nonwoven fabric.

Considering the mechanism of polymer crosslinking, which is an important part of the present invention, it is found that unsaturated monomers having lipophilic functional groups used in water-dispersible resin compositions tend to exist inside the particles, resulting in crosslinking inside the particles. To contribute.

Therefore, even if the Tg of the polymer is set low, the crosslinking of the polymer is strong, so even if the polymer is flexible, it can maintain normal tensile strength, tensile strength at heat, and water and alkali resistance. Moreover, since the unsaturated monomer having a hydrophilic functional group is relatively present on the particle surface due to its hydrophilic property, it is assumed that the functional group contributes to interparticle crosslinking. Therefore, if sufficient crosslinking occurs between particles, a tough film will be formed even if it is flexible. Furthermore, it is estimated that by using a partially methylated methylolmelamine resin in combination with this water-dispersible resin composition, even stronger interparticle crosslinking can be formed, and a stronger film can be formed.

The present invention will be explained in more detail below.

The water-dispersible resin composition of the present invention comprises styrene, (meth)acrylic acid alkyl ester, unsaturated glycidyl compound,
It can be obtained by emulsion polymerization of an unsaturated monomer consisting of an unsaturated methylol compound and an unsaturated dicarboxylic acid in the presence of an emulsifier according to a conventional method.

The (meth)acrylic acid alkyl esters used in the present invention are represented by the following formula (1).

(In the formula, R is a hydrogen atom or a methyl group, and R2 has 2 to 2 carbon atoms.
8 represents an alkyl group. ) Among them, one of the esters of ethyl, propyl, butyl, and 2-ethylhexyl of acrylic acid or methacrylic acid.
More than one species is preferably used.

In addition, in the present invention, in order to impart a strong crosslinked structure within and between particles to the water-dispersible resin composition to be produced,
Unsaturated monomers with reactive functional groups are used as essential components. Examples of unsaturated monomers having such reactive functional groups include compounds shown in (II) to (IV) below, and unsaturated monomers (■) having these reactive functional groups.

Each of (m) and (IV) can be used alone or in combination.

1 represents -C-0- or 10-).

Examples of (II) include glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, allyl glycidyl ether, and among these, glycidyl methacrylate is preferred.

NH(m) R, -0H (in the formula, R5 and R8 represent a hydrogen atom or a methyl group, and R7 represents an alkylene group having 2 to 4 carbon atoms).

- Examples of formula (m) include N-methylolacrylamide, N-methylolmethacrylamide, N-methylolcrotonamide, N-(2-hydroxyethyl)acrylamide, N-(2-hydroxyethyl)methacrylamide, N-( Examples thereof include 2-hydroxypropyl)acrylamide, N-(2-hydroxypropyl)methacrylamide, and among these, N-methylolacrylamide and N-methylolmethacrylamide are preferred.

(In the formula, R8 represents a hydrogen atom, a methyl group, or a carboxyl group; R9 represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or -CHCOOH, provided that at least one of R8 or R9 is a carboxyl group) .

- Examples of formula (IV) include itaconic acid, maleic acid, fumaric acid, etc.

All of the above are essential components, but in addition to these, a compound represented by the following general formula (V) may also be used in the copolymer when it is necessary to introduce a hydroxyl group into the copolymer to improve its physical properties. Used as a polymerization component.

(In the formula, 'R10' R11 is a hydrogen atom or a methyl group, B is -CH20- or -coo-1R12 is an alkylene group having 2 to 4 carbon atoms or 10 (CH2+2 to 4,
n represents a real number from 1 to 20).

Examples of general formula (V) include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxypolyoxyethylene acrylate, hydroxypolyoxyethylene methacrylate, hydroxypolyoxypropylene acrylate, hydroxypolyoxypropylene methacrylate, Hydroxypolyoxybutylene monoacrylate, hydroxypolyoxybutylene methacrylate, hydroxybutyl acrylate,
Examples include hydroxybutyl methacrylate, hydroxyethyl allyl ether, hydroxypropyl allyl ether, hydroxybutyl allyl ether, hydroxyethyl crotonate, hydroxypropyl crotonate, hydroxybutyl crotonate, and among these, hydroxyethyl methacrylate or hydroxypropyl methacrylate is preferred. .

In addition, acrylamide, methacrylamide, etc. can also be used by copolymerization.

In addition to these monomers, lower fatty acid vinyl esters such as vinyl acetate, vinyl propionate, and vinyl butyrate, nitriles such as acrylonitrile and methacrylonitrile, styrenes such as α-methylstyrene and chlorstyrene, vinyl chloride, and Vinyls such as vinyl chloride, vinylidenes such as vinylidene chloride and vinylidene bromide, butadiene,
Dienes such as chloroprene isoprene, vinylpyridine, etc. are used.

The usage ratio of the unsaturated monomers (II) to (IV) having reactive functional groups with the styrene and unsaturated monomer (1) is 9
971-7G/30 (weight).

In the present invention, styrene is necessary for imparting normal tensile strength, hot tensile strength, and water/alkali resistance to the water-dispersible resin composition, and the unsaturated monomer (1) is It is necessary to set the temperature of 7 g of the polymer in the composition to 10°C to 40°C, and can impart normal tensile strength, tear tensile strength, and flexibility to the binder, as well as water resistance and alkali resistance. In addition, the composition ratio of styrene and unsaturated monomer (1) used in the water-dispersible resin composition of the present invention is arbitrary only when the Tg of the polymer is set within the range of 10 ° C. to 40 ° C. However, preferably styrene/unsaturated monomer (the ratio is 60/40 to γ5/25).

In addition, in the present invention, styrene and unsaturated monomer (I
) If the usage ratio of ) is lower than 70, the polymerization stability during emulsion copolymerization will be poor, resulting in formation of gelled products during polymerization and gelation during storage of the water-dispersible resin composition obtained by emulsion copolymerization. may occur.

Furthermore, in the present invention, unsaturated glycidyl compounds (unsaturated monomers (n)'), unsaturated methylol compounds (unsaturated monomers (■)) and unsaturated dicarboxylic acids (unsaturated monomers (■)) ) are each used in the range of 0.2 to 1G weight %, but if both the unsaturated glycidyl compound and the unsaturated methylol compound are used in large amounts, they will gel during polymerization, and if both are used in small amounts, the desired physical properties will be affected. I can't get it. Moreover, if the former is large and the latter is small, the tensile elongation and tear strength of the workpiece will decrease, and vice versa, the tensile strength and tensile strength at heat will decrease. The unsaturated dicarboxylic acid contributes to interparticle crosslinking together with the unsaturated methylol compound, but if it is used in a large amount, gelation occurs during polymerization. In addition, if the amount is small, the interparticle crosslinking density will be low, and the physical properties of the processed product will be deteriorated.

A more preferable proportion of unsaturated monomers used in the present invention is as follows: 58-85% by weight of styrene, 39-21% by weight of monomer (1), 2-61i% by weight of monomer (II), monomer of (III). 1.5 to 4% by weight (mV) of monomer and 0.5 to 4% by weight of monomer (mV) are preferred. Furthermore, the solid content ratio of the partially methylated methylolmelamine resin to the water-dispersible resin composition of the present invention is 80.
/20 to 9515 is also preferably used in combination.

The water-dispersible resin composition of the present invention can be produced using conventional emulsion polymerization. The emulsifier and polymerization initiator used in this emulsion polymerization are not particularly limited, but they should be selected so that polymerization can be carried out smoothly depending on the unsaturated monomer system. As emulsifiers, anionic surfactants and nonionic surfactants can be used or used in combination, but reactive emulsifiers and/or parallax may be used to improve the mechanical stability of the synthetic resin emulsion. It is preferable to use reactive monomers such as sodium styrene sulfonate, sodium vinyl sulfonate, sodium metaallylsulfonate, and 2-aminomethylpropanesulfonic acid. As a polymerization initiator, persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, benzoyl peroxide,
Peroxides such as t-butyl hydroperoxide and cumene hydroperoxide are commonly used, but
Particularly suitable are water-soluble initiators.

Regarding the setting of the Tg of the polymer, if the Tg of the polymer is set lower than 10° C., the normal tensile strength and tensile strength at heat of the binder decrease. Also, if the Tg of the polymer exceeds 40°C, this will lead to a decrease in the tear tensile strength of the binder and a loss of flexibility. Therefore, the Tg of the polymer needs to be set at 10°C to 40°C.

〔Example〕

The present invention will be explained in more detail with reference to Examples below.

In addition, parts and percentages in the examples are based on weight unless otherwise specified.

Example 1 Water 44 parts Polyoxyethylene alkyl sulfate (10% aqueous solution) 7.5 parts 2-acrylamide, 2-methylpropanesulfonic acid (10% aqueous solution) 3 parts Styrene
30 parts 2-ethylhexyl acrylate 18 parts 2-hydroxyethyl methacrylate 3 parts Glycidyl methacrylate 1.5 parts N-methylol acrylamide 1 part Itaconic acid 0.5 parts Using a water-soluble polymerization initiator, the reaction temperature was adjusted by semi-batch method. Emulsion polymerization was carried out at 80 to 85°C to obtain a water-dispersible resin composition having a Tg of 19°C. To the thus obtained water-dispersible resin composition, partially methylolated melamine (Milpen SM-800, manufactured by Showa Kobunshi ■) was added in an amount of 15% by solid content to obtain a binder. This obtained binder was applied to a polyester nonwoven fabric with a resin adhesion amount of 1
7%/web (solid content) was impregnated and the physical properties were measured.

Example 2 1.5 parts of glycidyl methacrylate in Example 1 was added to 0.5 parts, and 1 part of N-methylolacrylamide was added to 2.5 parts.
Emulsion polymerization was carried out in the same manner as in Example 1, except that the amount was changed, and the physical properties were measured in the same manner as in Example 1 using the obtained water-dispersible resin composition.

Example 3 The same method as in Example 1 was carried out except that maleic acid was used instead of itaconic acid in Example 1.

Comparative Examples 1 to 8 Comparative examples were carried out in the same manner as in Example 1 except that the composition of the unsaturated monomer in Example 1 was changed as shown in Table 1.

The above results are summarized in Table-1 and Table-2.

[Non-woven fabric reviewer]

l) Preparation of resin-treated nonwoven fabric A polyester spunbond nonwoven fabric with a fiber basis weight of approximately 110 g/- has a binder solid content of 17%/w based on the fiber basis weight.
15 after impregnating to adhere eb (dry) amount.
It was dried at 0°C for 3 minutes and then heat-treated at 180°C for 3 minutes.

2) Tensile strength measurement Using an Instron type tensile testing machine (manufactured by Shimadzu Corporation), tensile test and tear test in an atmosphere of 20°C, 160°C
A tensile test was conducted in an atmosphere of

3) Alkali resistance measurement The resin-treated nonwoven fabric was immersed in an aqueous calcium hydroxide solution with a pH of 13 at 50°C for 10 days, then washed with water and thoroughly dried. The alkali resistance tensile strength retention was determined by conducting a tensile test in an atmosphere of

Table 2 Evaluation results of nonwoven fabrics O: Very good 0: Good . Nonwoven and paper binders with relatively low Tg tend to exhibit low resistance to heat and low mechanical strength. Although the water-dispersible resin composition of the present invention has a relatively low Tg, it has excellent normal tensile strength, tear tensile strength, hot tensile strength, water resistance, alkali resistance, and flexibility for nonwoven fabrics and paper. There is.

Therefore, it is extremely effective as a binder for waterproofing roofs, bathrooms, etc., as well as for automobiles, vehicles, filters, civil engineering sheets, nonwoven fabrics for daily life, and paper.

Claims (1)

[Claims] Styrene-(meth) is obtained by emulsion polymerization of styrene and (meth)acrylic acid alkyl ester in the presence of 0.2 to 10% by weight of each of an unsaturated glycidyl compound, an unsaturated methylol compound, and an unsaturated dicarboxylic acid. )
consisting of a water-dispersible resin composition of an acrylic acid alkyl ester copolymer, and the copolymer has a glass transition point of 1.
A water-dispersible resin composition for impregnating nonwoven fabric or paper, characterized in that the temperature is 0 to 40°C.