JPS58183772A - Adhesive for plywood of sliced veneer - Google Patents

Abstract

PURPOSE:The titled adhesive, prepared by adjusting the pH to a specific value with a masking agent in incorporating a synthetic rubber latex with an amino type resin to give a one-pack type product, and having improved operability with the prevented exudation to the surface of a sliced veneer and cracking phenomena in the surface of the sliced veneer. CONSTITUTION:An adhesive prepared by adjusting the pH to 6.0-9.0 with a masking agent, preferably 0.2wt% or more, based on 100pts.wt. one-pack type product, triethanolamine, in incorporating 100pts.wt., based on the solid content, synthetic rubber latex, preferably containing a copolymeric emulsion of a conjugated diene, e.g. butadiene, and a vinyl monomer, e.g. styrene, as a main component and a reactive monomer, e.g. having a carboxyl or amino group, etc., having functional groups crosslinkable with an amino resin with 50-600pts.wt., based on the solid content, amino resin, e.g. a condensation resin of an amino compound, e.g. urea or melamine, with formaldehyde, to give the one-pack type product.

Description

[Detailed description of the invention] The present invention relates to an adhesive for decorative plywood veneer.

For more details, see 4-4-
This article relates to a new single-component adhesive for decorative plywood veneers, which is a one-component blend of synthetic rubber latex and amine resin suitable for use in veneer coatings.

Conventionally, a veneer intermediate plate was pasted onto a wood-treated baseboard (hereinafter referred to as the baseboard) such as general plywood, particle board, sofa board, etc., with the aim of imparting the aesthetic appearance characteristic of wood to the surface. The combined product, ie, the veneer-decorated product, is used as a veneer-decorated product and is used for furniture, walls, flooring, ceiling materials, etc.

Decorative veneer products are different from general plywood from a practical point of view, and the beauty of the veneer surface increases the product value.
) (-), therefore contamination and defects on the surface of the veneer, such as oozing of adhesive onto the surface of the veneer and scuffing of the veneer veneer, etc., must be absolutely avoided.

Therefore, the adhesives used to bond and manufacture the base plate and the veneer veneer include various modified synthetic rubber latex and amino resin based adhesives, such as those known in Japanese Patent Publication No. 56-34196. etc., but all of these adhesives had to be transported, transferred, and mixed on-site by students themselves.5 Therefore, several types of similar substances had to be mixed and prepared on-site. In addition, it is not only troublesome, but also prone to mixing mistakes, and has the drawbacks of extremely poor workability. In history, for example, the special public service of 1983
An adhesive known in Publication No. 39829T4, which is called a liquid type and already contains synthetic rubber latex, amino resin, and cornstarch, has been proposed, but this adhesive has poor storage stability. However, the viscosity of the adhesive must be set in a high viscosity range such as 150 to 300 poise and 725°C, and the workability and productivity of bamboo manufacturing are also extremely poor. It was 11th
1 In addition, when the material type of the veneer is changed, changing the blending ratio of synthetic rubber latex, amine resin, cornstarch, etc. will prevent the adhesive from seeping onto the veneer surface.
The actual level has not been reached because flexible measures are strongly required to prevent dry cracking on the surface of the veneer.

The present invention is an adhesive that has been used for a long time when manufacturing veneered decorative plywood, etc., and is highly workable because it is a one-component stabilized synthetic rubber latex and amino resin. The objective is to provide a novel 1-kifuku drug whose compounding ratio can be changed flexibly depending on the needs of the field during compounding.

As a result of intensive research to achieve this, the present inventors have found that a masking agent is used when compounding synthetic rubber latex and amine resin and monoxidizing the mixture.
By adjusting the speed to ~9.0, we have completed the present invention by eliminating the drawbacks mentioned above.

That is, the present invention provides amine resin and crosslinked resin 1i, L
Synthetic rubber latex solid content with functional groups +00
It is an adhesive for veneer decorative plywood with an agent of 144 and a circle of 6.0 to 9.0.

1- The adhesive for decorative plywood of the present invention as described above is a stable blend of synthetic rubber latex and amine resin, which is liquefied to improve workability when compounding the adhesive, and to improve the workability of materials such as veneers. It is an adhesive for decorative plywood veneer with extremely high practical value that can be flexibly adapted to prevent the above-mentioned oozing contamination and dry cracking even when the width changes significantly.

The synthetic rubber latex having a functional group that undergoes a crosslinking reaction with the amino resin used in the present invention is the first IJ! V
+ as a conjugated die of butadiene or isogrene/,
The main component is a copolymer emulsion consisting of vinyl monomers such as styrene, methyl acrylate, methyl methacrylate, and acrylonitrile as the second component, and the functional groups that can crosslink with amino resins include carboxyl group, N-methylol group, and glycidyl group. Synthetic rubber latex whose third component is a reactive monomer selected from groups, hydroxyl groups, amine groups, amide groups, acid anhydrides, etc. A certain reactive monomer ratio is 011 to 20 with respect to the total amount of the first component and the second component.
% by weight is preferred.

In addition, the solid content concentration in the rubber latex listed in E is 1 streetcar 4
It is 0 to 60% by weight.

The amine resin used in the present invention includes a known so-called urea,
There are condensation resins of one or more amino compounds such as melamine and guanamines with formaldehyde, and modified resins in which these resins are partially modified with phenols, furfuryl alcohol, polyvinyl alcohol, etc. The molar ratio of formaldehyde) and /(amine compound) is usually 1.0 to 2.0, and the solid content is usually 45 to 72% by weight of the resin.

The blending ratio of the synthetic rubber latex and the amine resin in the present invention is 50 to 600 parts by weight, preferably 100 to 500 parts by weight, in terms of the solid content of the amine resin, per 100 parts by weight of the synthetic rubber latex solid content. It is. However, if the amount of the amine resin blended is less than 50 parts by weight, there is a tendency to cause some problems in the storage stability of the blended and liquefied amount, and at the same time, there is a tendency for dry adhesion when used as an adhesive. Adhesiveness tends to be insufficient. On the other hand, the blending ratio is 6
If the amount exceeds 0.00 parts by weight, the adhesive's ability to prevent leakage and contamination on the surface of the veneer and the resistance to drying and cracking on the surface of the veneer, which are the lifeblood of the adhesive, tend to be insufficient.

Next, the masking agent used in the present invention refers to a masking agent that is used in known so-called chelate titrations.
Examples include triethanolamine, dimethylcaptopropanol, dimethylcaptropropanesulfonic acid,
Examples include sulfosalicylic acid and thioglycolic acid.

In particular, from the viewpoint of storage stability in terms of blending and liquefaction, a combination system with the above-mentioned masking agent containing triethanolamine as a main ingredient is preferred.

The amount of the masking agent added in the present invention is not quantitatively determined based on the amount of liquefaction in the mixture of the synthetic rubber latex and amine resin, but the addition amount is determined by adjusting the pH to 6.0 to 9.0. This amount depends on the pH of the synthetic rubber latex and amino resin before blending, but usually 0.2% by weight is required based on 100 parts by weight of the blended liquefied product. Further, the concentration of the masking agent to be used can be determined by appropriately diluting it with water in advance. PH adjustment is
6. If OI' is adjusted to the acidic region, especially in the blended liquefaction amount, it will abnormally thicken and gel, and furthermore, separation phenomena will occur, resulting in a marked deterioration in storage stability, making it difficult to put it into practical use. It becomes impossible. Furthermore, if the yen] is adjusted to a highly alkaline region such as 9.0 or more, not only will the storage stability of the blending and liquefaction amount be similarly impaired, but especially the adhesion conditions during the production of veneer decorative plywood, 1!1j Unless strict conditions are set, such as setting the hot pressing temperature to a higher temperature or extending the pressing time, the curing speed will be slow, resulting in punctures in the veneer and poor adhesion, making it impossible to put it to practical use.

An example of a preferred manufacturing method for blending and liquefying the synthetic rubber latex and amine resin according to the present invention is as follows.

First, synthetic rubber latex is added to amino resin at room temperature and mixed and stirred. After being mixed uniformly 1. A masking agent having an adjusted concentration, such as a triethanolamine aqueous solution, is gradually added to adjust the pH to an arbitrary point between 6.0 and 9.0.

It is preferable to adjust the viscosity of the blended and liquefied amount to 1 o poise/25° C. or less, both from the viewpoint of productivity and from the viewpoint of transportation and liquid transfer.

In addition, regarding the method of using this blending and liquefaction amount, fillers and extenders that are conventionally blended into decorative veneer plywood or adhesives for manufacturing plywood, such as flour, clay, calcium carbonate, etc.
Contains talc, water, etc., usually has a viscosity of 18f, +so~300
Adjust to poise/25℃ before use.

Known curing agents such as ammonium chloride, hydrochloric acid, etc. used for curing amine-based resins may also be used in combination.1. The adhesive for veneer decorative plywood obtained in this way is applied to the plywood and adhered by a conventional method, but in this case, the amount of application is usually 98 to +49 dust per 900 cJ of the base plate, and the heat pressure temperature is 105 to 130'. C1 shows sufficient adhesion performance under adhesion conditions of 50 to 90 seconds of heat-pressing time. .

A combination of the synthetic rubber latex obtained by the present invention and an amino resin - the amount of liquefaction is excellent in storage stability, and can be adjusted arbitrarily depending on the purpose of use An adhesive with excellent convexity and workability It can be used as adhesive for thin veneer decorative plywood, thick veneer decorative plywood, paper pasted decorative processed products, mosaic perkerat pasted decorative processed products, etc.It has an extremely wide range of use and has high practical value. It is an adhesive.

Next, the present invention will be specifically explained with reference to Examples, Comparative Examples, etc., but the present invention is not limited to the following Examples.

In addition, in the following, parts and percentages are based on heavy/soft standards unless otherwise specified.

Example 1 Synthetic rubber latex adhesive (Mitsui Toatsu Chemical, K.

Manufactured by Structbond 1021, solid content 50%
) 50 parts, urea melamine resin adhesive (manufactured by Mitsui Toatsu Chemical, K., trade name: Niroid 12o1 solid content 72%) 5
0 parts were mixed and stirred, and 0.5 parts of a 50% triethanolamine aqueous solution was added to obtain a blending-liquefy amount of synthetic rubber latex and amine resin whose PL was adjusted to 8.0.

The viscosity of the obtained formulation at 25°C measured using a glue-on viscometer viscometer was N030-tar-30r, p
. 1η. It was 4°0 poise.

In addition, the liquefied amount of this mixture was placed in a polyethylene bottle of 51, and the viscosity was measured after standing for 3 months at 40°C, 125°C, and 5°C, and the appearance properties, etc. When observed, the viscosity of each at 25°C was 4.2.4° to 3.4°] poise. In addition, no changes were observed in the appearance and properties, indicating that the product had extremely good oral storage stability.

Further, like this (obtained with fc L, +1, blended - 100 parts of liquefied product (2), 68 parts of wheat flour, 31 parts of water and 1 part of ammonium chloride were added and blended, and the viscosity was 200 voids, 725 ° C. The resulting adhesive for decorative plywood was subjected to the following adhesive working conditions and adhesive performance tests.

(1) Bonding working conditions Plywood 2.7m/'m lauan plywood veneer veneer O03 "Ya Tsukuda Phillip Nara High moisture content coating amount 1209./771' Oven assembly time 3 minutes Closed assembly time 10 minutes Heat pressure conditions Clamping pressure 7 kg/'c, rl Clamping time 60 seconds Clamping temperature 110℃ (2) Adhesive performance test (a) Seepage contamination Visual observation (naked eye observation) (J) Adhesive force test (Type 2 immersion peel test )7.5L: TnX7゜5c
Seventy copies of the test piece cut into rn size were immersed in warm water at 3°C for 2 hours and then dried at a temperature of 60±3°C for 3 hours.

(...) Dry cracking test (cold heat cyclic test) Fix the test piece cut into a 15 cm square size with a metal frame L7
After that, 80 parts were left in a 3°C σ) +7i incubator for 2 hours, and then left in a thermostat at -20±3°C for 2 hours.
Repeat this several times and leave until it reaches room temperature. Table 1 shows the results of changes in viscosity measured using a Rion piscometer and visual inspection to determine the oral storage stability of the liquefied product.

In addition, Table 2 shows the results of the adhesive performance test of products bonded using the veneer decorative plywood adhesive obtained from the liquefied product with the formulation L.

Example 2 Synthetic rubber latex adhesive (Mitsui Toatsu Chemical, K.

(product name: Structbond 1021, solid content 50%)
50 parts, urea melamine resin adhesive (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name Niroid 120, solid content 72%) 1
50 parts were mixed and stirred, 0.47 parts of a 50% aqueous triethanolamine solution was added, and P)I was adjusted to 769 to obtain a liquefied product of the synthetic rubber latex and amino resin of the present invention. This was compounded as an adhesive for decorative plywood veneers and subjected to a storage stability test and an adhesive performance test in the same manner as in Example 1.

The results are shown in Table 1.2.

Example 3 Synthetic rubber latex adhesive (Mitsui Toatsu Chemical, K.

Product name, Structbond 1021, solid content 50%
)'50 parts, urea melamine resin adhesive (Mitsui Toatsu Chemical, manufactured by K., trade name Niroid 120, solid content 72%)
) 18 parts were mixed and stirred, 0067 parts of a 50% triethanolamine aqueous solution was added and blended, and the pH was adjusted to 8.0 to obtain a liquefied product of the synthetic rubber latex of the present invention and amino resin. 1 was blended as an adhesive for storage stability test and decorative plywood veneer in the same manner as in Example 1, and the adhesive performance test was conducted, and the results are shown in Table 1.2.

Example 4 Synthetic rubber latex adhesive (Mitsui Toatsu Chemical 1.K.

Product name: Structbond 1021, solid content: 50%)
50 parts, urea melamine resin adhesive (Mitsui Toatsu Chemical, K. Manufacturer name: Niroid 120 solid content 72%) 200
Mix and stir the 50% triethanolamine aqueous solution.
．． 35 parts were added and blended to adjust Yen 1 to 8.0 to obtain a blended liquefied product of the synthetic rubber latex and amino resin of the present invention. This was blended as an adhesive for storage stability tests and decorative plywood veneers in the same manner as in Example 1, and subjected to adhesive performance tests.
The results are shown in Table 1.2.

Example 5 Synthetic rubber latex adhesive (Mitsui Toatsu Chemical, K.

Product name: Structbond 1021, solid content: 50%)
50 parts, urea melamine resin adhesive (manufactured by Mitsui Toatsu Chemical, K., trade name Niroid 120, solid content 72%) 2
00 parts were mixed and stirred, and 50% thioglycolic acid hydroxide aqueous solution was added and blended to adjust the pH to 7.0 to obtain a liquefied product of the synthetic rubber latex and amino resin of the present invention.

As in Example 1, this product was subjected to a storage stability test and an adhesion test after being combined as an adhesive for decorative plywood veneer, and the results are shown in Table 1.2.

Example 6 Synthetic rubber latex adhesive (Mitsui Toatsu Chemical, K.

Manufactured by Structbond 1051, solid content 50%
) 50 parts, area resin adhesive (Mitsui Toatsu Chemical K.

Mix and stir 50 parts of Niloid 310, manufactured by K., and add 0.2 part of a 2.50% triethanolamine aqueous solution.
JI + was mixed, the pH was adjusted to 8.0, and the compound 1i of the present invention was added.
15 Compounding of rubber latex and amino resin - A liquefied product was obtained. This was blended as an adhesive for storage stability tests and decorative plywood veneers in the same manner as in Example 1, and subjected to adhesiveness passes tests.
The results are shown in Table 1.2.

Comparative Example 1 Synthetic rubber latex adhesive, area-melamine resin adhesive, and blending ratios were set the same as in Example 1 L, PI
- (Same as Example 1 except that 0.3 part of 20% caustic soda aqueous solution was added as a Q conditioner and the pH was adjusted to 8.0, mixed with cows - Liquefied products and adhesives were obtained and tested. The results are shown in Table 1.2.

Comparative Example 2 Synthetic rubber latex adhesive and area-melamine resin adhesive and the blending ratio were set the same as in Example 1, and o and i parts of a 28% ammonia aqueous solution were added and blended as a pH adjuster to adjust the pH to 8.0. A compounded liquefied product and an adhesive were obtained in the same manner as in Example 1, except for the adjustment, and subjected to each test, and the results are shown in Table 1.2.

Comparative Example 3 Synthetic rubber latex adhesive, area melamine resin adhesive, and blending ratio were set the same as in Example 1, and the pH was 1l.
50% triethanolamine aqueous solution 0.82 as a conditioning agent
Example 1 except that the pH was adjusted to 9.5.
Compounded and liquefied products and adhesives were obtained in the same manner as above and subjected to various tests, and the results are shown in Table 1.2.

Comparative Example 4 Synthetic rubber latex adhesive, area melamine resin adhesive and blending ratio were set to be the same as in Example 1, and 0.7 part of 50% thioglycolic acid aqueous solution was added as a pH adjuster to adjust the pH to 5.5. A compounded liquefied product and an adhesive were obtained in the same manner as in Example 1, except for the adjustment, and subjected to each test, and the results are shown in Table 1.2.

Claims (1)

[Claims] Solid content: 50 fEJt parts of synthetic rubber latex having a functional group capable of crosslinking with amine resin
When producing a liquefied veneer decorative plywood adhesive by blending ~600% amine resin, the pH was adjusted to 6.0 to 9.0 using a masking agent. Adhesive for decorative plywood veneers.