JPH03193302A - Ground processing method of surface-treated plywood or concrete form plywood - Google Patents

Abstract

PURPOSE:To improve sealing characteristics and prevent working environment from contaminating by a method wherein low-temperature curing aqueous resin is used for the resin component of ground coating resin. CONSTITUTION:As ground processing resin, low-temperature curing aqueous resin is used and set at a temperature lower than 60 deg.C. The low-temperature curing aqueous resin is resin composition prepared by mixing 1 - 99wt.% of aqueous polyurethane resin with one or more kinds of resin, which are selected from the group consisting of curable aqueous resin such as urea-formaldehyde resin, melamine-formaldehyde resin, phenol-formaldehyde resin, phenolmelamine- formaldehyde resin, phenolmelamine-urea-formaldehyde resin or the like, aqueous emulsion resin and aqueous polymeric isocyanate resin or resin composition prepared by further adding 20 - 80wt.% of filler to the resin composition just mentioned above.

Description

[Detailed Description of the Invention] C. Industrial Field of Application] The present invention relates to a method for treating the base of surface-treated plywood and concrete formwork plywood. By supplying a resin with a fast curing speed, it can be used as a base treatment resin in plywood manufacturing technology that particularly requires surface smoothness, and can provide improvements such as sealing properties, shortening manufacturing time, and simplifying manufacturing equipment. It is.

Furthermore, by using a water-based resin, the problem of contamination of the working environment due to organic solvent vapor when using general organic solvent-based coatings such as #J resin is solved.

[Prior art]

Regarding the surface treatment method for surface-treated plywood or concrete-coated formwork plywood, at present, there are limited amounts of resin used for surface treatment.
Solvent-based resins are often used, but due to recent circumstances, the problem of contamination of the working environment due to organic solvent vapor during manufacturing has become a serious factor, and non-existent solvent-based base treatment resins are attracting attention. be.

[Problem to be solved by the invention]

However, in order to avoid the above problems, curable water-based resin is known as a method of using non-organic solvent-based resin, but in this case, due to the curing characteristics of water-based resin,
It requires a high-temperature environment such as 0° C. to 100° C., and the phenomenon of thinning of the cured resin product is an unavoidable drawback.

Further, when using a curable aqueous resin, there are problems as described below, and it cannot be said to be completely satisfactory.

1) When a curable water-based resin is used as a base treatment resin, thinning occurs due to the loss of water contained in the resin composition. It is very difficult to do so.

2) When a curable water-based resin is used as the base treatment resin, if the moisture contained in the cured resin is removed, the intermediate coating resin and Various problems such as foaming of the top coat resin occur, leading to deterioration of the surface quality of the product.

In order to prevent this, after applying the base treatment resin, as a method to minimize the influence of moisture, it is necessary to take a long time to harden and dry the base treatment resin to allow the moisture to scatter, or to increase the drying temperature to a high temperature. (60°C to 100°C) and evaporates water. However, considering the constraints imposed by the manufacturing time, it is necessary to perform the processing at a high temperature.

In this case, the problem is that the drying shrinkage of the wood parts causes distortion in the plywood, making it extremely difficult to maintain a constant thickness of the top coat resin layer.

Further, if drying is performed at an unnecessarily high temperature, heat shrinkage occurs in the cured resin. Also, from the standpoint of product dimensional stability, high temperature treatment of plywood should be avoided.

Therefore, it is necessary to develop a base treatment resin that has good sealing properties, does not cause problems of contamination of the working environment, and can be cured at low temperatures, and to establish a base treatment technology for surface-treated plywood or concrete formwork plywood. However, this is an issue.

[Means to solve problems]

The present inventor focused on the low-temperature curing properties of water-based polyurethane resin and the shielding properties of the formed coating film, and by mixing this with conventional water-based resins, it was possible to form a special base treatment resin layer. So, the above il! They discovered that the problem could be solved, and finally arrived at the present invention.

That is, the present invention relates to (1) a surface treatment method for surface treated plywood and concrete form plywood, which is characterized in that a low-temperature curing aqueous resin is used as a resin component in the undercoat resin; Method of manufacturing frame plywood.

(2) A low-temperature curing water-based resin is used as the base treatment resin and is cured at 60°C or less (1).
) Surface treatment method for plywood or concrete formwork plywood.

(3) Low-temperature curing water-based resins include urea/formaldehyde resin, melamine/formaldehyde resin, phenol/formaldehyde resin,
Curable aqueous resins such as formaldehyde resins, phenolmelamine/formaldehyde resins, phenolmelamine/urea/formaldehyde resins, or one or more resins selected from the group of aqueous emulsion resins or aqueous polymer/isocyanate resins, (1) above, which is a low temperature curable aqueous resin prepared by mixing 1 to 99% by weight of an aqueous polyurethane resin, or a resin composition formed by further mixing 20 to 80% by weight of a filler to the resin composition. This invention relates to a surface treatment method for surface-treated plywood or concrete formwork plywood.

According to the method of the present invention, in the surface treatment of surface-treated plywood or concrete formwork plywood, especially in the method of surface treatment of plywood that requires surface smoothness, thinning and hardening of the cured resin for surface treatment are possible. By using the properties of water-based polyurethane to prevent moisture movement within the product, the above-mentioned conventional problems can be solved and the surface smoothness can be significantly improved.

The low-temperature curing aqueous resin used in the present invention is an aqueous resin composition that can be cured at a temperature of 60°C or lower, such as urea/formaldehyde resin, melamine/formaldehyde resin, phenol/formaldehyde resin, phenol/melamine/melamine/formaldehyde resin, etc. One or more resins selected from the group of formaldehyde resins, curable aqueous resins such as phenolmelamine/urea/formaldehyde resins, aqueous emulsion resins, or aqueous polymer/isocyanate resins, from 1 to 99% by weight. , preferably 10~
A resin composition comprising a low-temperature curing aqueous resin mixed with 50% by weight of the following aqueous polyurethane resin, or a resin composition comprising a further 20 to 80% by weight of a filler added to the resin composition. Appropriate.

When using the above-mentioned curable aqueous resin, it is appropriate to use 0.1 to 5% by weight of the curing agent based on the curable aqueous resin.

The above-mentioned water-based polyurethane resin is manufactured using, for example, the following raw materials.

That is, the following diisocyanate and the following glycol and a glycol having a carboxylic acid group are reacted to form a urethane.

As the diisocyanate used at this time, known aliphatic, alicyclic or aromatic diisocyanates can be used.

Such diisocyanates include, for example, 2.4-
) lylene diisocyanate, 2.6-) lylene diisocyanate, 4,4'-diphenylmethane diisocyanate, m-phenylene diisocyanate, xylylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate ester, 1,4-cyclohexylene diisocyanate, 4 .4°-dicyclohexylmethane diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate, 3.3′-methoxy-4,4′-biphenylene diisocyanate, 1.5-naphthalene diisocyanate, 1.5-tetrahydronaphthalene Examples include diisocyanate, isophorone diisocyanate, and known isocyanate-modified products such as carbodiimide-modified products, biuret-modified products, and urethane-modified products of these diisocyanates.

A mixture of two or more of these diisocyanates can also be used.

Examples of glycols include glycol ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, trimethylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, bisphenol A, and ethylene to bisphenol. Low molecular weight glycols such as oxide adducts, polyethers such as polyols such as polyethylene glycol and polypropylene glycol, and polyesters which are condensates of ethylene glycol and adipic acid, hexanediol and adipic acid, and ethylene glycol and phthalic acid. , polycaprolactone, etc., or a mixture of two or more of these glycols.

As the glycol having a carboxylic acid group, for example, 2
．． 2-dimethylolpropionic acid, 2.2-dimethylolacetic acid, 2,2-dimethylolvaleric acid, etc., or a mixture of two or more of these glycols having a carboxylic acid group are used.

Further, as a crosslinking agent for the above water-based polyurethane, for example, 2,2-bishydroxymethylbutanol Tris C3
-CI-aziridyl)propionate], diphenylmethane-bis-4,4'-N, N"-diethylene urea, and other compounds containing at least one aziridine group are suitable.

The appropriate amount of the crosslinking agent used in the aqueous polyurethane is 0.1 to 5% by weight.

The water-based polyurethane resin made from the above raw materials can form a film with excellent adhesion, water resistance, and shielding properties, and can also improve surface smoothness by improving sealing properties as a base treatment resin. By preventing water movement from the cured resin layer for base treatment and the plywood, suppressing the foaming phenomenon of the top coat resin caused by water, and using a low temperature curing resin, it is possible to eliminate the problems that conventionally occur due to heating. It was possible to prevent the occurrence of distortion due to drying shrinkage of the plywood, and to obtain a quality with excellent surface smoothness.

According to the present invention, due to the curing characteristics of the water-based polyurethane resin, low temperature curing is possible, and the thinning of the cured base treatment resin after curing is reduced, and the surface smoothness is improved.
Good gloss.

Moreover, even when compared with the physical properties of existing concrete formwork plywood, it has performance that is equivalent or better, making it possible to improve the quality of the product.

The base treatment resin used in the present invention is a curable water-based resin, and does not cause environmental pollution problems unlike solvent-based resins.

〔Example〕

EXAMPLES Hereinafter, in order to explain the present invention more specifically, Examples and Comparative Examples will be given and explained, but the present invention is not limited to these Examples.

The raw materials used in the Examples and Comparative Examples of the present invention are as follows.

Melamine/urea cocondensation resin: U- manufactured by Mitsui Toatsu Chemical ■
777 Aqueous polymer resin di-synthetic rubber latex, MR-113 manufactured by Mitsui Toatsu Chemical ■ Aqueous polyurethane resin: HU101 manufactured by Mitsui Toatsu Chemical ■ Crosslinking agent A: 2.2-bishydroxymethylbutanol Tris (3-( 1-Aziridyl) propionate] PZ-33° crosslinking agent B manufactured by Nippon Shokubai Kagaku Kogyo ■: Polymethylene polyphenylene polyisocyanate (manufactured by Mitsui Toatsu Chemical ■: trade name Q?-CI?-200).

Crosslinking agent C: A crosslinking agent for an aqueous polymer resin containing polymethylene polyphenylene polyisocyanate. 5B-225H manufactured by Mitsui Higashi Mitsui Toatsu Chemical ■.

Example 1 The base treatment resin was melamine/urea cocondensation resin 50
50 parts by weight of the aqueous polyurethane resin were mixed, and 0 parts by weight of crosslinking agent A was added to 100 parts by weight of the mixture.
．． 5 parts by weight and 0.5 parts by weight of ammonium chloride as a hardening agent.
5 parts by weight was added, and a filler (calcium carbonate) was added as filler % in the solid content of the mixed composition [=pigment weight content]. Hereinafter, it will be abbreviated as PWC. ) is mixed to 70%, and apply 8 to 10 gr of the mixture on the surface of the plywood for formwork.
/8 cm and dried for 5 minutes at 40'C.

The above-mentioned base-treated plywood was further coated with 1 part by weight of crosslinking agent A added to 100 parts by weight of water-based polyurethane as a top coat resin at a rate of 5 gr/2.

Example 2 The base treatment resin was melamine/urea cocondensation resin 50
50 parts by weight of an aqueous polymer resin is mixed with 50 parts by weight of the water-based polymer resin, 5 parts by weight of an aqueous polyurethane resin is added to 50 parts by weight of the mixed resin, and 0.5 parts by weight of a crosslinking agent A is added to 100 parts of this mixed resin. , 2 parts by weight of crosslinking agent B, 0.5 parts by weight of ammonium chloride as a hardening agent, and a mixture of filler (calcium carbonate) to give a PWC of 70% were added to the surface of the plywood for formwork. It was coated at ~10 gr/shaku2 and dried at 40°C for 5 minutes.

The above-mentioned base-treated plywood was further coated with 1 part by weight of crosslinking agent A added to 100 parts by weight of water-based polyurethane as a top coat resin at a rate of 5 gr/2.

Example 3 The base treatment resin was added to 50 parts by weight of the water-based polymer resin.
50 parts by weight of water-based polyurethane resin were mixed, 2.5 parts by weight of crosslinking agent C and 0.5 parts by weight of crosslinking agent A were added to 100 parts by weight of the mixture, and filler (calcium carbonate) was added to 70% PWC. Apply the mixture to the surface of the plywood for formwork at a rate of 8 to 10 gr/shaku2, and
It was dried at 0°C for 5 minutes.

The above-mentioned base-treated plywood was further coated with 1 part by weight of crosslinking agent A added to 100 parts by weight of water-based polyurethane as a top coat resin at a rate of 5 gr/2.

Comparative Example 1 The base treatment resin was melamine/urea cocondensation resin 10
0 parts by weight, 1 part by weight of crosslinking agent A per 100 parts by weight of the mixture, and 0 parts of ammonium chloride as a curing agent.
．． Added 5 parts by weight and further added filler (calcium carbonate) to P.
A mixture of 70% WC was applied to the surface of plywood for formwork at a rate of 8 to 10 gr/2 and dried at 40°C for 5 minutes.

The above-mentioned base-treated plywood was further coated with 1 part by weight of crosslinking agent A added to 100 parts by weight of water-based polyurethane as a top coat resin at a rate of 5 gr/2.

Comparative Example 2 The base treatment resin was melamine/urea cocondensation resin 50
Mix 50 parts by weight of an aqueous polymer resin with respect to parts by weight;
To 100 parts of this mixed resin, 1 part by weight of crosslinking agent B, 0.5 part by weight of ammonium chloride as a hardening agent, and a filler (calcium carbonate) was mixed to give a PWC of 70%. 8-10 gr on the surface of the formwork plywood
/shaku 2 and dried at 40°C for 5 minutes.

To the above-mentioned base-treated plywood, 1 part by weight of crosslinking agent A was added to 100 parts by weight of water-based polyurethane as a top coat resin, and was applied at a rate of 5 gr/2.

Comparative Example 3 The base treatment resin was prepared by mixing 5 parts by weight of crosslinking agent C with 100 parts by weight of water-based polymer resin, and further mixing filler (calcium carbonate) to a PWC of 70%. Apply it to the surface of the plywood at a rate of 8 to 10 gr/shaku2,
It was dried at 40°C for 5 minutes.

The above-mentioned base-treated plywood was further coated with 1 part by weight of crosslinking agent A added to 100 parts by weight of water-based polyurethane as a top coat resin at a rate of 5 gr/2.

The evaluation results are shown in Table 1.

The physical properties measurement method shown in Table 1 was based on the Japanese Agricultural Standards for plywood for concrete mold frames.

〔Effect of the invention〕

According to the present invention, due to the curing characteristics of the water-based polyurethane resin, low temperature curing is possible, and the thinning of the cured base treatment resin after curing is reduced, and the surface smoothness is improved.
Good gloss.

Furthermore, even when compared with the physical properties of existing concrete formwork plywood, it is clear from Table 1 that it has the same or better performance, so it is possible to improve the quality of the product.

Table 1 O...No abnormality ×...Poor coating layer condition

Claims (1)

[Claims] 1. Surface-treated plywood or concrete formwork, which is characterized in that a low-temperature curing water-based resin is used as a resin component in the undercoat resin, regarding a surface treatment method for surface-treated plywood and concrete formwork plywood. How to prepare the plywood surface. 2. The method for surface treatment of surface treated plywood or concrete form plywood according to claim 1, wherein a low temperature curing water-based resin is used as the base treatment resin and is cured at 60° C. or lower. 3. The low temperature curable aqueous resin is a curable aqueous resin such as urea/formaldehyde resin, melamine/formaldehyde resin, phenol/formaldehyde resin, phenolmelamine/formaldehyde resin, phenolmelamine/urea/formaldehyde resin, or an aqueous emulsion resin or aqueous The surface-treated plywood according to claim 1, which is a low-temperature curing water-based resin made by mixing 1 to 99% by weight of a water-based polyurethane resin with one or more resins selected from the group of polymer/isocyanate resins. Or how to prepare the groundwork for concrete form plywood. 4. A base for surface-treated plywood or concrete formwork plywood according to claim 3, wherein the low-temperature curing aqueous resin is a mixture of the resin composition according to claim 3 and 20 to 80% by weight of a filler. Processing method. 5. The method for surface treatment of surface-treated plywood or concrete formwork plywood according to claim 3, characterized in that 0.1 to 5% by weight of the hardening agent is used with respect to the curable water-based resin. 6. 0.1 to 5% by weight based on water-based polyurethane resin
4. The method for surface treatment of surface-treated plywood or concrete form plywood according to claim 3, characterized in that a crosslinking agent of: