JPH0655982B2 - Method for producing highly foamable binder composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [1] Field of Industrial Application The present invention relates to a foamable binder composition for foaming and adhering. More specifically, the present invention relates to a method for producing an emulsion-type highly foamable binder composition mainly composed of vinyl acetate and ethylene.

[2] Conventional technology Conventionally, vinyl acetate and ethylene and N- as a cross-linking agent
Binders obtained by emulsion copolymerization of methylol compounds or N-alkoxy compounds or products using the binders are known. For example, French Patent No. 1,564,100 discloses a solvent for a film produced from a vinyl acetate-ethylene copolymer emulsion. In order to increase the resistance and improve the high mechanical stability of the film, N-methylol compounds such as N-methylolacrylamide, N-methylolmethacrylamide and N-alkoxy compounds such as methyl or butyl ether thereof are used as a crosslinking agent. It has been shown to be used in amounts of 0.5 to 10% by weight, based on vinyl acetate, to allow the copolymer to crosslink at temperatures from room temperature to 180 ° C, preferably in the presence of a curing agent. U.S. Pat.Nos. 3,345,318 and 3,380,851 also include vinyl acetate-
It is described that the emulsion polymerization of an ethylene-N-methylol acrylamide copolymer and the use of such an emulsion as a binder in the application of a nonwoven fabric having excellent water resistance and solvent resistance are described.

That is, the non-woven fabric using such an emulsion as a binder is water resistance, solvent resistance as described in JP-A-52-55709, and in addition, the vinyl acetate-ethylene copolymer has the inherent performance, namely light resistance, heat resistance, Heat resistance of conventional styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, synthetic rubber latex such as methyl acrylate butadiene copolymer as a binder due to having a characteristic of being excellent in embossing suitability,
It has been widely used in this field because of its improved light resistance and inferior heat resistance and embossing suitability when using an acrylic copolymer emulsion as a binder.

There are many methods for producing a non-woven fabric, such as an adhesive type, a needle punch type, a spunlace type, a stitch bond type and a spun bond type, but the present invention is mainly used for the adhesive type. The adhesive type is a method in which loosely collected fiber lumps (webs) are integrated with a binder, and the loosely collected fiber lumps (webs) are impregnated with the binder, adhered by printing, spraying or other method, and dried. It is a manufacturing method.

As described above, the binder is dried by impregnation, printing, spraying, or any other method, but the form of the binder to be adhered is not only water but also water and air. There is. The latter is a method in which a normal emulsion binder composition is foamed and the foam is attached. (Hereinafter, it is referred to as a foam adhesion method.) In order to uniformly adhere a fixed amount of the binder solid component to a large adhered area, the binder must be diluted with water when only water is used as the medium. When water and air are used as the binder, the volume of the binder can be increased by foaming, so that it is not necessary to dilute the binder composition with water, that is, the binder solid content concentration can be increased in the foam adhesion method. As a result, in the foam adhesion method, it is dried (evaporated) in the drying process.
Since the amount of water is small, the drying energy cost can be greatly reduced, and since the amount of evaporated water is small, the emulsion solids are entrained in the evaporation of water from the inside during the drying process, and Since the phenomenon of migration to the surface of (1) is suppressed and the strength of the adherend is improved, the foam adhesion method has received much attention. Such a situation is the same in the woven fabric processing regardless of natural fibers such as natural cellulose-based, polyester-based, polyamide-based, rayon-based and synthetic fibers. Hereinafter, non-woven fabric and woven fabric are collectively referred to as non-woven fabric and the like.

[3] Problems to be Solved As described above, the foam adhesion method has received a great deal of attention, and as a result, it is desired that the binder composition be capable of foaming as high as possible. It shall not reduce the water resistance or solvent resistance of the manufactured processed product. It was difficult to satisfy both the water resistance and solvent resistance of the processed product and the high foamability of the binder composition at the same time. The present invention has been completed by finding out a specific manufacturing method using a specific combination.

[4] Means for Solving the Problems The present invention is directed to vinyl acetate and ethylene and the general formula (R ₁ represents H or CH ₃ , and R ₂ represents H or an alkyl group having 5 or less carbon atoms.) As an essential component, and the weight ratio thereof is 52 to
(A) Copolymer emulsion having a ratio of 96.5: 40 to 3: 8 to 0.5
Production of a highly foamable binder composition characterized by adding 2 to 10 parts by weight (as solid content) of (B) higher alcohol sulfate ester surfactant to 100 parts by weight (as solid content) Regarding the method.

The copolymer emulsion of [A] will be described in detail.

The monomer represented by the general formula (1) is, for example, N-methylol (meth) acrylamide (refers to both N-methylol acrylamide and N-methylol methacrylamide; the same applies hereinafter), N-methoxymethyl (meth) acrylamide, N- Ethoxymethyl (meth) acrylamide,
N-butoxymethyl (meth) acrylamide etc. can be mentioned. The monomer represented by the formula (1) does not have to be one type, and may be a mixture of two or more types.

Further, in the present invention, the copolymerization amount of the compound of the general formula (1) is limited to 0.5 to 8 in terms of weight ratio in order to obtain sufficient water resistance and solvent resistance depending on the final required performance of the nonwoven fabric using a binder. This is for giving. That is, the general formula (1)
If the amount of the compound is less than 0.5, a sufficient cross-linking effect cannot be obtained, and even if copolymerizing 8 or more, a product showing more excellent performance cannot be obtained.

In the present invention, the ethylene copolymerization amount is limited to a weight ratio of 3 to 40 in order to be appropriately changed from a hard texture to a soft texture according to the final required performance of a nonwoven fabric using a binder. A product with an ethylene content and at least a weight ratio of 3 or more to be copolymerized with ethylene in order to provide sufficient water resistance, while a copolymer with a weight ratio of 40 or more has a soft texture. Is not obtained.

The copolymer emulsion of [A] does not have to be composed only of vinyl acetate, ethylene and the monomer represented by the general formula (1), but may be methyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid. Octyl, various (meth) acrylic acid esters such as glycidyl (meth) acrylate, various unsaturated acids such as acrylic acid, itaconic acid, maleic acid, (meth) acrylamide, vinylsulfonic acid (or its salt), 2-hydroxy Ethyl (meth) acrylamide, vinyl chloride, vinylidene chloride, styrene, butadiene, acrylonitrile, maleic acid, adipic acid,
It is also possible to appropriately copolymerize a diallyl ester such as phthalic acid, a triallyl ester of benzenetricarboxylic acid, a polypolymerizable monomer such as triallyl isocyanurate, and the like. The method for producing the copolymer emulsion [A] is not particularly limited. Emulsifiers include, for example, completely or partially saponified polyvinyl alcohol, fiber-based derivatives such as methyl cellulose, hydroxyethyl cellulose, various nonionic or anionic water-soluble polymers such as α-olefin-ammonium salt of maleic anhydride, polyoxyethylene alkyl ether, Various nonionic surfactants such as polyoxyethylene alkyl phenyl ether, polyoxyethylene polyoxypropylene block copolymer, polyoxyethylene sorbitan fatty acid ester,
Examples include anionic surfactants such as lauryl sulfate soda salt, dialkyl succinate, and alkylbenzene sulfonate, and these are used alone or as a mixture. A redox type initiator is desirable as the polymerization initiator. Examples of the oxidizing agent include ammonium persulfate,
Examples thereof include potassium persulfate, sodium persulfate, hydrogen peroxide, and various organic peroxides. The persulfate salt is particularly preferably used because the persulfate salt and its decomposition product also serve as a crosslinking catalyst. Examples of the reducing agent include formaldehyde sodium sulfoxylate, a reaction product of glyoxal and a salt of reducing sulfur oxide, and the like. further
Additives such as pH adjusters and electrolytes can also be used by known emulsion polymerization techniques. The polymerization conditions such as polymerization pressure and polymerization temperature are not particularly limited, but generally the polymerization temperature is 0 to
It is practical to maintain in the range of 100 ° C, preferably in the range of 30-80 ° C. Also, the polymerization pressure is arbitrarily adjusted depending on the amount of ethylene in the desired copolymer, and 5 to 100 kg is necessary to obtain an ethylene copolymerization amount of 3 to 40 in weight ratio.
A polymerization pressure of / cm ² is utilized. The solid content concentration in the emulsion can be adjusted by the amount of monomers to be copolymerized and water, but a solid content concentration of about 40 to 60% by weight is suitable from the viewpoint of industrial use.

For [B] higher alcohol sulfate ester surfactant
Details will be described. The higher alcohol sulfate ester system
General formula R-O6CH₂-CH₂-O_nSO ₃M  (2) (R represents an alkyl group having 8 or more carbon atoms. N is 0 to 1
It is an integer value of 0. M is a monovalent cation and is not particularly limited
There is no. ).

Surfactants can be broadly classified into four types: anionic type, cationic type, amphoteric type, and nonionic type. 4th of these
When a cationic surfactant such as an ammonium salt or an alkylpyridinium salt is added to and mixed in the emulsion of the present invention, emulsion particles aggregate to form grits, or, in a remarkable case, the binder composition as a whole gels. Is not suitable as a foaming agent for. The reason why the grits are generated or the binder composition is gelled is that the emulsion particles are generally charged with anions not only when using the anionic emulsifier but also when using the nonionic emulsifier. Conceivable. Amphoteric surfactants such as betaines and amine oxides have good foamability in the binder composition, but are found from the experimental results that the water resistance and solvent resistance of processed products are significantly inferior, and Not fit for purpose.

Nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, polyoxyethylene sorbitan alkyl esters are water resistant and solvent resistant products of processed products. However, it was found that the binder composition was insufficient in foamability and was not preferable. Next, the anionic surfactant.
When anionic surfactants are divided by polar groups, there are carboxylates, sulfates, sulfonates, phosphates, etc., and many surfactants exist. Various investigations on these surfactants have revealed that the specific surfactant represented by the general formula (2) has excellent foamability, and that the processed product has excellent water resistance and solvent resistance. It was. Although some sulfonates have good foamability, the processed products were inferior in water resistance and solvent resistance.
Further, the carboxylic acid salts and phosphoric acid ester salts were insufficient in the foamability of the binder composition. The surfactant [B] will be described in more detail. Although R is an alkyl group, it must have 8 or more carbon atoms. If the number of carbon atoms is less than 8, foamability is insufficient, which is not desirable. n is an integer of 0 to 10. If the number exceeds 10, the foamability will be insufficient. M
Is a monovalent cation, and sodium ion, potassium ion, ammonium ion, triethanolammonium ion and the like are exemplified as having the same foaming property.
Ammonium ion and triethanolammonium ion are generally superior in foam stability, but depending on the final end use, it may be better to avoid them due to odor and coloring of processed products. It can be selected according to demand. That is, there is no particular limitation as long as it is a monovalent cation. However, sodium ion is the standard because of price and generality in the industry. Divalent cations are remarkably inferior in foamability and are unsuitable.

The usage ratio of the copolymer emulsion of [A] and the higher alcohol sulfate ester-based surfactant of [B] is [A]: [B] =
It is 100: 2 to 10 (solid content weight ratio). If the amount of the surfactant is too small, the foamability will be poor. On the contrary, if the amount of the surfactant is too large, the foamability will reach the limit, but the processed product will contain a large amount of unnecessary surfactant, which is not suitable. The higher alcohol sulfate ester surfactant does not have to be one compound. As long as the higher alcohol sulfate ester-based surfactant is used, it can be mixed and used without any problem, and other surfactants other than the higher alcohol sulfate ester-based surfactant can be used together. However, the use of a surfactant other than the higher alcohol sulfate ester-based surfactant in the same amount (solid content weight) or more as the surfactant is for the purpose of the present invention, that is, the water resistance of the processed product,
It is not preferable because the solvent resistance and the foamability of the binder composition cannot be simultaneously improved.

The copolymer emulsion of [A] and the higher alcohol sulfate ester-based surfactant of [B] have been described above. The binder composition includes [A] and a crosslinking agent such as a known amino resin other than [B], A cross-linking catalyst, a foam stabilizer, a foam stabilizer, a filler, a dispersion stabilizer, a wetting agent, a thickener, and the like may be used as necessary, and a known emulsion and latex other than [A] may be used in combination. Is also good.

The production method of the present invention is obtained by adding a specific amount of the (B) higher alcohol sulfate ester-based surfactant to the (A) copolymer emulsion, and (B) a higher alcohol sulfate. The ester surfactant acts as a foaming agent. It is known that a higher alcohol sulfate ester-based surfactant is used in a copolymerization reaction to obtain a copolymer emulsion. However, such a technique is to use the surfactant before (or during) the copolymerization reaction. It is added, where the surfactant acts as an emulsifier. Therefore, the present invention has features different from the above-mentioned known techniques.

To produce a non-woven fabric using the binder composition obtained by the present invention, the foamed binder composition is brought into contact with the powder-bonded or pre-bonded web obtained by a method such as a wet method and a dry method, and then the back surface is contacted. It may be pulled in under reduced pressure, or may be pressed or bubbles may be pushed in by a plate-like material to be attached to the inside of the nonwoven fabric and dried and heat-treated. The bubbles are broken when they enter the nonwoven fabric and wet the nonwoven fabric fibers. The foaming method, the foam adhering method, the drying method, the heat treatment method, and the like used therein and the equipment therefor may be those devised in a known manner and are not limited in any way.

To obtain the effect of the cross-linking reaction, 100 to 180 ° C, preferably
It is suitable to heat-treat at a temperature of 120 to 150 ° C for 1 to 20 minutes.

Thus, a non-woven fabric having a high degree of water resistance and solvent resistance can be obtained.

Similar to non-woven fabrics, valuable products can be obtained by applying to woven fabric processing fields other than non-woven fabrics, for example, texture modifiers, gamming agents, knit size stabilizers, waterproofing agents, and printing binders.

Hereinafter, the present invention will be described in more detail with reference to Examples and Examples, but the present invention is not limited thereto.

[5] Reference Example and Example 1. Reference Example (1) (Production of Copolymer Emulsion) A 100 pressure resistant reactor equipped with a reaction temperature controller and a stirrer was charged with the following.

32000g Water 365g Hydroxyethyl cellulose having an ethylene oxide addition mole number of 2.5 800g Polyoxyethylene nonylphenol ether of HLB17 800g Polyoxyethylene nonylphenol ether of HLB14 These ingredients were heated and stirred for 1 hour to completely dissolve them.
The charge was cooled to about 30 ° C. before adding the following.

8250g vinyl acetate 16g acetate 20g sodium acetate 0.8g FeSO ₄ 2880g 8% glyoxal - oxygen was removed by purging the reactor with aqueous sodium bisulfite nitrogen and ethylene,
The charge was then heated to 45 ° C. During the heating period, ethylene was added to adjust the pressure to 60 kg / cm ² , 8% ammonium persulfate aqueous solution was added, and at the time when the polymerization was started, the following two supplies were started. The first was 20,000 g of vinyl acetate and the feed was at a constant rate for 4 hours. Second
The product is N-methylol acrylamide 55 in 2000 g of water.
With 0 g dissolved, the feed was carried out at a constant rate over 5 hours. During this period, ethylene was kept constant at a polymerization pressure of 60 kg / cm ² . The polymerization was terminated when the unreacted vinyl acetate monomer decreased to 0.32% in the polymerization time of 9.5 hours.
The emulsion obtained had a solid content of 50% by weight, the ethylene content calculated from the mass balance was 25% by weight,
The methylolacrylamide content was 1.3% by weight. The emulsion obtained is called.

Reference Example (2) (Production of Copolymer Emulsion) Polymerization was performed in the same manner as in Reference Example (1) except that equimolar formaldehyde sodium sulfoxylate was used in place of glyoxal sodium bisulfite. The solid content of the obtained emulsion was 50% by weight, the ethylene content calculated from the mass balance was 25% by weight, and the N-methylolacrylamide content was 1.3% by weight. The emulsion obtained is called.

Reference Example (3) N-methylol acrylamide of Reference Example (1) was set to 410 g, and vinyl acetate 20,000 supplied after the polymerization was started.
g was supplied after 820 g of Nn-butoxymethylacrylamide was added and dissolved, and ethylene was fed at a polymerization pressure of 45
The same procedure as in Reference Example (1) was performed except that kg / cm ² was used. The solid content of the obtained emulsion was 50% by weight, the ethylene content calculated from the mass balance was 17% by weight, the N-methylolacrylamide content was 1.0% by weight, and the Nn-butoxymethylacrylamide content was 2.0%. % By weight. The emulsion obtained is called.

Reference Example (4) (Production of Copolymer Emulsion) Same as Reference Example (2) except that 2,825 g of 20,000 g of vinyl acetate supplied after the initiation of polymerization is replaced with 2-ethylhexyl acrylate and supplied. I went to. The solid content of the obtained emulsion was 50% by weight, the ethylene content calculated from the mass balance was 25% by weight, the N-methylolacrylamide content was 1.3% by weight, and the 2-ethylhexyl acrylate content was 7% by weight. there were. The emulsion obtained is called.

Reference Example (5) (Production of Copolymer Emulsion) 32,000 g of water in Reference Example (1) was replaced with 52490 g and 800 g of HLB1.
119 polyoxyethylene nonylphenol ether of 7
The same procedure as in Reference Example (1) was performed except that 0 g of sodium lauryl sulfate was changed to 800 g of HLB14 polyoxyethylene nonylphenol ether to 410 g.

The emulsion obtained is called.

2. Examples 1 to 8 and Comparative Examples 1 to 17 Using the emulsions prepared in Reference Examples, and various surfactants, various formulations were made so that the solid content ratio shown in Table 1 was obtained, and adjusted with water. Therefore, the solid content concentration is 12
A wt% of each binder composition was obtained. The obtained binder composition is a foaming machine composed of an adjusting machine for keeping the air supply constant, an adjusting machine for keeping the binder composition supplied, and a mixing head (eg, MINIMIX (WERNER MATHIS product name).
Made by AG (Switzerland))) to the maximum foaming rayon 100
% Non-woven web and pulled from the back side under reduced pressure to soak the rayon web so that the solid content of the binder composition is 18% by weight, then dry at 130 ° C. for 1.5 minutes, and then Heat treatment was performed at 130 ° C. for 10 minutes to prepare a nonwoven fabric having a basis weight of 45 g / m ² . The performance of these non-woven fabrics is also shown in Table 1. The residual free formaldehyde (hereinafter abbreviated as FF) in the processed product may cause a problem depending on the final end use, so the FF is measured for reference. The test conditions are as follows. The tensile strength was measured in accordance with the tensile strength test method of JIS L-1085 non-woven fabric test method.

(1) Dry tensile strength: Measured in a standard condition of 20 ° C. and 65% RH.

(2) Water resistance: Tensile strength after immersion in water at 20 ° C for 30 minutes.

(3) Solvent resistance: Tensile strength after immersion in methyl ethyl ketone or gasoline at 20 ° C for 30 minutes.

(4) FF: Free formalin of the non-woven fabric was measured by JIS L-1041 and JIS L-1096 (acetylacetone method, sample 2.5 g).

(5) Maximum expansion ratio: The maximum expansion ratio obtained by the above MINIMIX was determined at a liquid temperature of 20 ° C.

The results of the performance evaluation of the non-woven fabric are shown in Table 1 and the foamability is shown in Table 1. In all emulsions, the higher alcohol sulfate ester-based surfactant gives good results in water resistance, solvent resistance and foamability at the same time. It is clear that

Various surfactants used Sodium lauryl sulfate C ₁₂ H ₂₅ OSO ₃ Na Ammonium lauryl sulfate C ₁₂ H ₂₅ OSO ₃ NH ₄ Polyoxyethylene lauryl ether sodium sulfate C ₁₂ H ₂₅ O (CH ₂ CH ₂ O) _n SO ₃ Na n = 3 Dioctyl sulfosuccinic acid sodium salt N-alkyl sulfosuccinic acid monoamide disodium salt (Brand name Perex TA (Kao Soap Company name)) Dodecylbenzenesulfonic acid sodium salt Polyoxyethylene nonylphenol ether sulfate sodium salt Polyoxyethylene lauryl ether C ₁₂ H ₂₅ O (CH ₂ CH ₂ O) _n H n = 6 Polyoxyethylene nonylphenol ether Dimethyl lauryl amine oxide Dimethyl lauryl ammonio acetate (lauryl betaine) Polyoxyethylene nonylphenol ether (HLB1
7) n = 30 [6] Effects of the Invention As described above, the present invention provides a method for producing a binder composition having good water resistance, solvent resistance, and foamability at the same time.

Front Page Continuation (72) Inventor Takeo Oyamada 1-5 Anezaki Kaigan, Ichihara, Chiba Sumitomo Chemical Co., Ltd. (56) References Japanese Patent Publication No. 49-23299 (JP, B1) Japanese Patent Publication No. 48-39390 ( JP, B1) JP-B-57-28484 (JP, B2)

Claims (1)

[Claims] 1. Vinyl acetate and ethylene and the general formula (R ₁ represents H or CH ₃ , and R ₂ represents H or an alkyl group having 5 or less carbon atoms.) As an essential component, and the weight ratio thereof is 52 to
(A) Copolymer emulsion having a ratio of 96.5: 40 to 3: 8 to 0.5
Production of a highly foamable binder composition characterized by adding 2 to 10 parts by weight (as solid content) of (B) higher alcohol sulfate ester surfactant to 100 parts by weight (as solid content) Method.