JPS61247776A - Adhesive for felt - Google Patents

Abstract

PURPOSE:To provide the title adhesive capable of reducing the amount of static electricity, by homogeneously mixing a resin for a felt with starch to obtain an impalpable powder. CONSTITUTION:100pts.wt. resin for a felt comprising a phenolic resin (e.g.: novolac resin + curing agent) is sufficiently mixed with 1-40pts.wt. starch (e.g.: beta-starch) with a mixer to obtain an impalpable powder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a felt adhesive used as a binder for fibers during the production of felt.

[Prior Art] Conventionally, resins used as binders in the production of felt are mainly fine powders of phenolic resins.

The fibers used are often a mixture of natural fibers and chemical fibers in various proportions.

Therefore, in conventional felt manufacturing, if a large amount of chemical fiber is mixed or the humidity is low, product defects due to static electricity will increase. To prevent such static electricity, (1)
Eliminate static electricity using quaternary ammonium salt antistatic agents, (2) conductive substances such as carbon fibers and carbon powder, or (3) substances that are the same as or have a similar charge series as the material to be neutralized. There is a known method of mixing it with a substance to make it into a product.

However, methods using these antistatic agents are expensive, and if they are incorporated to the extent that antistatic effects are achieved, the product cost increases significantly, and the antistatic effect is not sustainable, so the product cannot be used for a long period of time. If you keep it in stock, it will have an antistatic effect.

In the method using carbon fibers and carbon powder, since the binder for felt is a fine powder with an average particle size of about 2 μm, the conductivity will not improve unless it is added to the fifth grade. Therefore 5
If it is added to the felt, the appearance of the felt will become black and the product value will be lost.

Furthermore, carbon fibers and carbon powders are generally expensive, which increases product costs and makes them unsuitable for practical use.

In the above-mentioned method of mixing a substance with a charge series rank close to the other material, since felt is a mixture of various fibers, the range of charge series ranks is wide, and therefore it is difficult to select a substance with a similar charge series rank. Therefore, in this method as well, especially when the fibers have a high proportion of chemical fibers and the humidity is low, product defects due to static electricity increase.

[Problems to be Solved by the Invention] The present invention overcomes the above-mentioned drawbacks, and reduces the amount of static electricity generated during felt manufacturing without significantly reducing the strength of felt. The purpose of the present invention is to provide an adhesive for felt that quickly attenuates the electrostatic charge, reduces product defects due to static electricity generated during felt manufacturing, has an excellent long-lasting antistatic function, and prevents deterioration of the working environment due to dust. .

[Means for Solving the Problems] The felt adhesive of the present invention is composed of a felt resin and 1 to 40 parts by weight of starch based on 100 parts by weight of the felt resin. The starch is characterized by being in the form of a uniformly mixed fine powder.

The felt resin constituting the felt adhesive of the present invention is mainly a phenolic resin produced using phenols. This phenolic resin can be a resin obtained by reacting at least phenols and aldehydes. The phenolic resin is obtained by reacting phenols and aldehydes in the presence of a catalyst, and conventionally known phenolic resins can be used. That is, conventionally known phenolic resins such as novolac resins obtained by condensing phenols and aldehydes under a t5M catalyst, resol resins obtained under an alkaline catalyst, and other modified phenolic resins can be used.

The phenolic resin and the like are preferably composed of a novolak resin and a curing agent. A polyamine or the like is used as the curing agent, and hexamethylenetetramine is particularly preferred.

The other main component of the felt adhesive of the present invention is starch. This starch may be α-starch or β-starch, or a mixture of both. Among these starches, β-starch is preferred. This is because β-starch is usually in the form of a fine powder and has excellent miscibility and homogeneity with the felting resin. Note that the particle size, particle shape, grain crystal shape, type of raw material, etc. of these starches are not particularly limited. This starch, for example β-starch,
It can be collected from potatoes, sweet potatoes, corn, wheat or tapioca. It may also be a mixture of these.

The blending ratio of the above β-starch is 100% felt resin
[1 to 40 parts by weight (hereinafter referred to as PHR) per part i. When the blending ratio is less than 1 PHR, it is not effective against static electricity, and when it exceeds 40 PHR, it is effective against static electricity, but the strength and stiffness of the felt deteriorate, making it unusable.

The felt adhesive is in the form of a fine powder in which the felt resin such as the phenolic resin and the starch are uniformly mixed. Note that the starch is usually added in a predetermined amount to the felt resin during the pulverization process during the production of the felt adhesive.

The method for producing the felt adhesive is not particularly limited, but typical examples include the following method. That is, a predetermined amount of phenol and a predetermined amount of formalin are placed in a reaction vessel, oxalic acid, etc. are added as a catalyst, and the mixture is allowed to react in a reflux state for approximately one and a half hours. After that, slaked lime is added to neutralize the mixture, and then the mixture is heated to a predetermined temperature. The felt resin is produced by dehydration under reduced pressure. Further, a predetermined amount of starch, a hardening agent, etc. are thoroughly mixed with a predetermined amount of the resin using a mixer, and then the mixture is coarsely pulverized and finely pulverized to produce a felt adhesive.

[Action 1 Starch is a white powder contained in potatoes, sweet potatoes, corn, tapioca, etc., and is a type of polysaccharide. This starch easily absorbs moisture in the atmosphere, thereby improving conductivity and easily dissipating generated static electricity to the outside of the system. This conductivity is said to come from the molecular structure in addition to water, but this has not yet been theoretically clarified.

The felt adhesive containing a predetermined amount of the above starch reduces the amount of static electricity generated during felt manufacturing, and quickly attenuates the generated static electricity.
Product defects due to static electricity can be reduced during felt manufacturing.

[Effect of R-light] The felt adhesive of the present invention is composed of a felt resin and 1 to 40 parts by weight of starch based on 100 parts by weight of the felt resin. is characterized by being in the form of a uniformly mixed fine powder.

This starch easily absorbs moisture from the atmosphere and has properties suitable for eliminating static electricity, so this felt adhesive reduces the generation of static electricity and easily releases the generated static electricity to the outside of the system. . Therefore, the starch has a pH of 1 to 40 PH.
This felt adhesive containing R reduces troubles and product defects caused by static electricity during felt manufacturing without significantly reducing the strength of the felt, reduces dusting, increases the yield of additive resin, and improves the yield of additive resin. It is possible to prevent deterioration of the working environment.

In addition, compared to antistatic agents such as quaternary ammonium salts and conductive substances such as carbon powder, the cost of the above starch is low, and even when it is incorporated into products, the cost does not increase. Furthermore, the fourth
It has superior antistatic properties compared to antistatic agents such as grade ammonium salts, and there is little risk that the antistatic effect will decrease even when the product is stopped for a long time.

[Example] The present invention will be explained below with reference to Examples.

Example 1 100 parts of a normal novolac type phenolic resin, 12 parts of hexamethylenetetramine, 1 part of calcium stearate, and 2 parts of corn β-starch were thoroughly mixed in a mixer, and coarsely and finely ground to produce a felt adhesive. did. The electric charge amount and water content were measured using this adhesive for felt, and the results are shown in the table.

To prepare 100 parts of the above novolac type phenolic resin, 96 parts of phenol and 62 parts of 37% formalin were placed in a reaction vessel, 0.1 part of oxalic acid was added as a catalyst, the reaction was carried out under reflux for 1.5 hours, and then slaked lime was added. After neutralization, dehydration was performed under reduced pressure to 160°C.

Example 2 A felt adhesive was produced in the same manner as in Example 1, except that 40 parts of the same cough β-starch was used instead of 2 parts of β-starch used in Example 1, and the adhesive was charged in the same manner as above. The volume and moisture content were measured and the results are shown in the table.

Comparative Example A felt adhesive was produced in the same manner as in Example 1, except that 1 part of lauryltrimethylammonium chloride was used instead of 2 parts of β-starch, and the charge amount and water content were The results are shown in the table.

According to the results in the table, in the case of Examples 1 and 2, the amount of charge was significantly reduced compared to the comparative example, and the effect against static electricity was significantly superior. Furthermore, when the amount of β-starch blended is 2 parts (Example 1), the water content is almost the same as that of the comparative example, and when the amount of β-starch blended is 40 parts (
Example 2), its water content is significantly higher than that of the comparative example. Therefore, in terms of water content, Example 2 has a significantly better effect against static electricity than Comparative Example.

From the above, when the blending amount of β-starch is 1 to 40 PHR, the strength of the felt is maintained to a certain extent compared to conventional products, while the effect on static electricity is significantly improved and product defects due to static electricity are reduced. can do.

Claims (5)

[Claims] (1) Consisting of a felting resin and 1 to 40 parts by weight of starch based on 100 parts by weight of the felting resin,
A felt adhesive characterized in that the felt resin and the starch are uniformly mixed in the form of fine powder. (2) The felt adhesive according to claim 1, wherein the felt resin is a phenolic resin obtained by reacting at least phenols and aldehydes. (3) The felt adhesive according to claim 2, wherein the phenolic resin is composed of a novolak resin and a hardening agent. (4) The adhesive for felt according to claim 1, wherein the starch is β-starch. (5) The adhesive for felt according to claim 4, wherein the β-starch is extracted from potato, sweet potato, corn, wheat, or tapioca.