JPS6399363A - Binder for nonwoven fabric - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved binder for nonwoven fabrics, particularly for improving strength,
The present invention relates to a binder for nonwoven fabrics that can yield nonwoven fabrics with excellent solvent resistance, water resistance, etc.

[Prior art and its problems] There are several methods of binding fibers in dry-processed nonwoven fabrics: using a binder (binding agent), thermally fusing the fibers, and mechanically intertwining the fibers. This method is the most widely adopted because it can provide a variety of functions to nonwoven fabrics. Most of the binders used are mainly composed of an aqueous dispersion of polymer particles called latex or emulsion, and the types of polymers used include acrylic, vinyl acetate copolymers, SBR, and NBR. has been done.

The most important properties required of nonwoven fabrics are strength, durability, and a feel suitable for the intended use, and the performance of latex has a very large effect on these properties.

For example, in nonwoven fabrics for clothing interlining, if latex film strength, water resistance, and solvent resistance are not sufficient, the clothing will have poor shape retention and will not be able to withstand washing or dry cleaning. Furthermore, even in nonwoven fabrics used for general industrial materials and miscellaneous goods, the strength and durability required for each use are largely influenced by the performance of the latex.

For the above reasons, in order to improve strength and durability, the latex used as a binder is copolymerized with functional monomers such as N-methylol (meth)acrylamide, which has crosslinking reactivity, or water-soluble trimester is used. A commonly used method is to use a polyfunctional thermosetting resin such as rolled melamine resin during processing to form a crosslinked structure in the latex polymer during the heat treatment process of the nonwoven fabric.

However, these methods reduce the chemical stability of the latex, making it impossible to introduce large amounts of crosslinking components, and requiring long-term heat treatment at high temperatures to obtain sufficient effects. Therefore, satisfactory effects have not been obtained in the actual nonwoven fabric manufacturing process where productivity must be taken into account. Furthermore, in recent years, the proportion of polyester fibers used as fibers for non-woven fabrics has been rapidly increasing, but since this fiber is inherently difficult to bond, there is an increasing need for latex with excellent strength and durability. is the current situation.

The present invention has been made in consideration of the above-mentioned conventional circumstances, and aims to improve the problems that conventional binders for nonwoven fabrics have poor strength, water resistance, solvent resistance, etc., and insufficient durability. Describe what you mean.

[Means for Solving the Problems] In the process of developing and researching binders for nonwoven fabrics with excellent strength and durability, the present inventors found that in order to meet the increasingly sophisticated and diversified performance requirements, The present invention was developed based on the recognition that it is insufficient to improve a single polymer, and that the best method is to combine multiple polymers and maximize the characteristics of each. It is.

That is, the present invention contains a latex obtained by emulsion polymerization of a conjugated diene and/or an ethylenically unsaturated monomer in an aqueous medium containing a water-soluble or water-dispersible polymer made of an epoxy resin. This is a binder for nonwoven fabrics, which is characterized by:

The epoxy resin used in the present invention may be one that is dissolved or dispersed in water, and there are no particular restrictions on the IA production method, but the content of the surfactant added for the purpose of emulsification and dispersion is It is best to use as little as possible, and most preferably a self-dispersing type that does not contain a surfactant.

An example of the epoxy resin used in the present invention is shown below.

The epoxy resin used in the present invention is preferably an epoxy resin obtained by modifying the epoxy resin with another compound and introducing a segment with emulsifying power into the molecule to impart self-dispersibility.

For example, JP-A-53-1228 discloses a grafted epoxy resin obtained by polymerizing a monomer mixture containing a carboxylic acid monomer using a free radical generator such as benzoyl peroxide in the presence of an epoxy resin. It has been shown that resins can be stably dispersed in aqueous media containing bases. - As an example, there is a polymer represented by the structural formula (I> described below), and a commercially available product is Dick Fine GN-0280 (Dainippon Ink & Chemicals (!)).
1).

(Left below) In addition, JP-A-56-43362 discloses a composition in which an epoxy resin and a carboxyl functional polymer are reacted in the presence of a specific tertiary amine.

In addition, Japanese Patent Application Laid-open No. 55-3481 and No. 55-3482 disclose that a carboxyl group-functional polymer is esterified with an epoxy resin in the presence of an amine esterification catalyst, and self-dispersed in water using a base. Epoxy ester copolymers are disclosed.

The conjugated diene used in the present invention includes butadiene-1,3,2-methyl-butadiene-1,3,2-
Examples include chlorbutadiene-1, 3, etc., but considering copolymerizability with the monomer and economical efficiency, butadiene-1, etc.
It is preferable to use 1 and 3.

Examples of the ethylenically unsaturated monomer used in the present invention include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate,
Propyl methacrylate, butyl acrylate, butyl methacrylate, pentyl acrylate, pentyl methacrylate, hexyl acrylate, hexyl methacrylate, heptyl acrylate, heptyl methacrylate, octyl acrylate, octyl methacrylate, acrylic octadecyl, methacrylic acid Acrylic acid alkyl esters and methacrylic acid alkyl esters such as octadecyl; ethylenically unsaturated aromatic monomers such as styrene, α-methylstyrene, vinyltoluene, chlorostyrene, 2,4-dibromustyrene, etc. ; Acrylonitrile,
Unsaturated nitriles such as methacrylonitrile; acrylic acid,
methacrylic acid, crotonic acid, maleic acid and its anhydrides, fumaric acid, itaconic acid, and monoalkyl esters of unsaturated dicarboxylic acids, such as monomethyl maleate,
Ethylenically unsaturated carboxylic acids such as monoethyl fumarate and mono-n-butyl itaconate; vinyl esters such as vinyl acetate and vinyl propionate; vinylidene halides such as vinylidene chloride and vinylidene bromide; acrylic acid;
Hydroxyalkyl esters of ethylenically unsaturated carboxylic acids such as 2-hydroxyethyl, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, etc. Ethylenically unsaturated carboxylic acids such as glycidyl acrylate, glycidyl methacrylate, etc. glycidyl esters of: and acrylamide, methacrylamide, N-
Examples include radically polymerizable monomers such as methylol acrylamide, N-methylol methacrylamide, N-butoxymethyl acrylamide, and diacetone acrylamide.

The ratio of the water-soluble or water-dispersible polymer (A) made of the epoxy resin used in the present invention to the conjugated diene and/or ethylenically unsaturated monomer (B) is not particularly limited, but the solid content weight ratio So (A) / (B) = 5
/95 to 9515 is preferred.

The latex of the present invention is prepared by polymerizing a conjugated diene and/or an ethylenically unsaturated monomer in an aqueous medium containing a water-soluble or water-dispersible epoxy resin by a conventional emulsion polymerization method.

For example, a monomer mixture is dispersed in water in the presence of the water-soluble or self-dispersing polymer described above, and a free radical generating catalyst, such as KPS (K25203), APS
((NH4>23208>, preferably 4
Emulsion polymerization may be carried out at 0 to 90°C.

In this case, the amount of emulsifier added for the purpose of emulsifying and dispersing the conjugated diene and ethylenically unsaturated monomer in water is not particularly limited, but if the performance of the binder is taken into account, the temperature of the emulsifier in the aqueous phase is the critical micellar temperature. It is preferable that the emulsion polymerization concentration is below the concentration, and most preferably, the emulsion polymerization is carried out by utilizing the surface active effect of the water-soluble or water-dispersible polymer present in the aqueous phase without adding an emulsifier.

° The obtained polymer aqueous dispersion has a pH of 5 to 7 and a viscosity of 30 to
It has a pH of about 1000 cP, and is preferably adjusted to pH 8 to 9 with an alkaline solution to improve stability.

Furthermore, in the present invention, there is no problem in using additives commonly used in emulsion polymerization, such as chain transfer agents, polymerization stabilizers, and ethylenediaminetetraacetic acid for the purpose of buffering effects, as necessary.

The latex of the invention is concentrated to the required solids content, for example by methods such as stripping.

When using the obtained latex as a binder for nonwoven fabrics, cross-linking agents such as trimethylolmelamine resin and epoxy resin, cross-linking catalysts such as ammonium chloride and ammonium para-toluenesulfonate, stabilizers such as various surfactants, etc. There is no problem in using commonly used additives such as softeners and fluorescent dyes.

[Effects of the Invention] When a nonwoven fabric is processed using the binder containing the latex of the present invention obtained in this way, the nonwoven fabric has excellent strength, washing resistance, and dry cleaning resistance, and also has a range from very flexible to hard. Since nonwoven fabrics can be obtained that have a wide range of textures to suit various uses, they are ideal as nonwoven fabrics for clothing and materials. In addition, since it has good stability such as impregnability and sprayability, it can be used for other purposes such as coating materials, adhesives, paints, and foaming binders.

Next, the present invention will be specifically explained with reference to Examples.

Note that the number of copies shown in the text indicates parts by weight.

Example 1 50 parts of water-dispersed epoxy resin (Dick Fine GN-0280, manufactured by Dainippon Ink & Chemicals) as a solid content, 100 parts of ion-exchanged water, 50 parts of butadiene, and methyl methacrylate were placed in a nitrogen-substituted autoclave with a stirrer. 1
0 parts, acrylonitrile 40 parts, potassium persulfate 0.5
and polymerization was carried out at 60'C with stirring until the polymerization rate reached 85% or more.

Next, unreacted sludge was removed and concentrated by steam distillation, resulting in a pH of 8.1, a solid content of 50.0%, and a viscosity of 142.
Latex A8 of 0 cP was obtained. The polymerization reaction proceeded smoothly without the formation of aggregates, and Latex A was also extremely stable.

Next, latex A was cast onto a glass plate to a dry film thickness of 0.1 to 0.2 mm, and the resulting film was air-dried at 20°C for 48 hours and heated at 140°C for 5 minutes. , J.I.
A specimen was prepared by punching with a No. S1 dumbbell, and the strength and elongation of the film was measured using a Tensilon at a tensile speed of 500 mm/min. The film is highly elastic and tough, with a tensile strength of 2
The weight was 50 kg/cm2 and the elongation was 300%.

Next, to measure water resistance and solvent resistance,
Samples of m x 3 ctn and 5 cm x 5 cm were prepared and immersed in water and perchlorethylene for 1 day, and then the dimensional change rate (%) and areal swelling rate (%) were measured. The results showed that the dimensional change rate due to immersion in water was 0.5%.
It can be seen that latex A has an extremely excellent water resistance and solvent resistance, with an area swelling rate of 7.6% upon immersion in perclene.

Comparative Example 1 Water-dispersed epoxy resin (Dick Fine GN-028
Emulsion polymerization was carried out in the same manner as in Example 1, except that 1 part of sodium dodecylbenzenesulfonate (Neoken R1 manufactured by Daiichi Kogyo Seiyaku@) was used as an emulsifier without using V), and then unreacted monomers were used. 1) by removing and concentrating
A latex a with H8.0, solid content 50.0%, and viscosity 500CP was obtained.

Next, a film was prepared in the same manner as in Example 1, and the strength, water resistance, and solvent resistance of the film were measured. As shown in Table 1, the results showed that the strength, water resistance, and solvent resistance of the film were inferior to that of Latex A, which was 1q in Example 1, which is an example of the present invention.

Comparative Example 2 Latex A obtained in Comparative Example 1 and a water-dispersed epoxy resin were mixed at a solid content ratio of ioo:so to obtain latex A'.

Next, a film was prepared in the same manner as in Example 1, and the strength and elongation, water resistance, and solvent resistance of the film were measured. As shown in Table 1, latex A' was clearly inferior to latex A of Example 1, which is an example of the present invention, in terms of film strength and elongation, water resistance, and solvent resistance.

Example 2 Raw materials having the following composition were charged into a stainless steel reaction vessel equipped with a nitrogen-substituted stirrer, condenser, thermometer, and dropping funnel.

Deionized water
0.5% aqueous solution of 140Fe(,g-6820
0.4 Sodium formaldehyde sulfoxylate 0.3 Water-dispersed epoxy resin (solid content 20%) 50 Ammonia water (28%) 0.4 Neugen EA-1201 (polyoxyethylene nonylphenol ether, Daiichi Kogyo Seiyaku flavor! & Then, while maintaining the liquid temperature in the container at 2°C, 60 parts of a monomer mixture consisting of 86 parts of n-butyl acrylate, 10 parts of acrylonitrile, 2 parts of N-methylolacrylamide, and 2 parts of methacrylic acid were added. Additionally, a catalyst solution prepared by dissolving 0.3 parts of ammonium persulfate in 10 parts of deionized water was added dropwise over 180 minutes to polymerize, and stirring was continued for 60 minutes at the same temperature after the addition was completed.

After stirring, the contents were cooled to 30°C, adjusted to pl-17.2 with 28% ammonia water, and the solid content was 45°1%.
A stable latex B with a viscosity of 470CP was obtained.

Next, a film was prepared in the same manner as in Example 1, and the strength and elongation, water resistance, and solvent resistance of the film were measured. As shown in Table 1, the material exhibited high tensile strength despite being flexible, and had excellent water resistance and solvent resistance.

Comparative Example 3 Emulsion polymerization was carried out in the same manner as in Example 2 except that a water-dispersed epoxy resin was not used and 1 part of sodium alkyldiphenyl ether disulfonate was used as an emulsifier, and the pH was 7.5 and the solid content was 40.4. %, viscosity 180cP
latex b was obtained.

Next, a film was prepared in the same manner as in Example 1, and the strength and elongation, water resistance, and solvent resistance of the film were measured. As shown in Table 1, the results showed that the strength, water resistance, and solvent resistance of the film were inferior to that of latex B obtained in Example 2, which is an example of the present invention.

Comparative Example 4 Latex B obtained in Comparative Example 3 and a water-dispersed epoxy resin were mixed at a solid content ratio of ioo:20 to obtain latex B'.

Next, a film was prepared in the same manner as in Example 1, and the strength and elongation, water resistance, and solvent resistance of the film were measured. As shown in Table 1, the results showed that the strength, water resistance, and solvent resistance of the film were inferior to that of latex B obtained in Example 2, which is an example of the present invention.

(Margins below) Example 3 Latex A and latex B were each diluted with water to adjust the solid content to 10%, and then impregnated into a polyester web with a basis weight of 40 (]/m2 and dried for 5 minutes in IOO'C. 1
By baking at 50'C for 1 minute, a nonwoven fabric having a resin solid content/fiber ratio of 25/100 (weight ratio) was obtained. Next, nonwoven fabric stain test method (JISL-108
5), the morphological changes of the nonwoven fabric in the dry cleaning strength and washing strength tests of the nonwoven fabric were evaluated.

The results are shown in Table 2, Latex A, Latex B
The nonwoven fabric using this as a binder had extremely excellent strength, dry cleaning resistance, and washing resistance.

Table 2 Durability Comparative Example 5 of Processed Non-woven Fabrics a, Latex a, A', b, and B' were impregnated into non-woven fabrics and evaluated for durability in the same manner as in Example 3, respectively.

The results are shown in Table 3. Latex A, which is an example of the present invention,
1 Latex B was inferior in durability in all cases. Note that the evaluation criteria are the same as in Table 2.

Claims (1)

[Claims] (1) It is characterized by containing a latex obtained by emulsion polymerization of a conjugated diene and/or an ethylenically unsaturated monomer in an aqueous medium containing a water-soluble or water-dispersible polymer made of an epoxy resin. A binder for nonwoven fabrics.