JPS62171783A - Production of painted form plywood - Google Patents

Abstract

PURPOSE:To inexpensively manufacture excellent form plywood with high productivity by using a paint consisting of modified rubber latex as well as an amino resin curable by heating, filler and modifier in production of a concrete form. CONSTITUTION:The paint prepd. by compounding the amino resin such as urea resin, inorg. or org. filler, modification agents of various compds. and further pigment and curing accelerator with the modified rubber latex consisting of a copolymer of a compd. having a conjugated diene bond (1st component), vinyl monomer (2nd component) and reactive monomer (3rd component) is used and after such paint is coated on one or both faces of the form at about 200-300g/m<2> coated amt., the coating is predried at about 40-80 deg.C and is then subjected to heating and compressing for about 30-180sec at about 110-130 deg.C under about 10-30kg/cm<2>G pressure by a hot press or heater roll. Then, the substantial coated film is obtd. by one time of painting and since the paint is inexpensive and is cured in a short period, the productivity is high and the excellent form ply wood is obtd. The use of lower raw timber and considerable cost reduction are made possible.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an improved method of manufacturing painted formwork plywood.

(Prior art and its problems) In recent years, as the raw wood situation has worsened, relatively low-quality wood has come to be used for formwork plywood. Formwork plywood manufactured from such low-grade wood is used as concrete for civil engineering and construction work.
- When used as formwork, problems such as poor curing of concrete and contamination of the concrete surface with wood pigments occur. Furthermore, recently, a construction method called exposed concrete construction has been increasing mainly in the construction of public facilities, and a smooth concrete surface is required, but formwork plywood made from low-grade wood has a smooth surface. This is also a problem since the smoothness is poor.

In order to solve these problems, in recent years so-called painted form plywood, in which the surface of form plywood is coated with acrylic paint or urethane paint, has come to be manufactured and marketed, and the amount thereof is increasing year by year. However, when manufacturing coated form plywood by coating the surface of form plywood with acrylic paint or urethane paint, the following problems arise.

+11 When painting formwork plywood with acrylic paint or urethane paint, the coating film is thin with one coat, so two to three coats are usually required, and the work must be dried after each coat, making the work time-consuming. It is complicated and therefore the work efficiency is low.

(2) Since acrylic paints and urethane paints are thermoplastic, they are usually dried at room temperature, which takes a long time to dry.

(3) Acrylic paints and urethane paints contain organic solvents, and since these organic solvents volatilize during the drying process, equipment for recovering the volatilized organic solvents is required as a pollution control measure.

(4) Acrylic paints and urethane paints belong to the category of expensive paints, so using such paints on painted plywood, which is consumed in large quantities, would be costly.

The inventors of the present invention have solved these problems and, as a result of intensive studies on manufacturing coated formwork plywood with good workability and productivity and low cost, have developed a method using modified synthetic rubber latex and heat-curable amino acid. It was discovered that this problem could be solved by using a paint consisting of a resin and a modifier, and a patent application was filed in 1980-28.
The application was filed as No. 3841.

However, when producing painted formwork plywood using a paint made of the above-mentioned modified synthetic rubber latex, heat-cured amino resin, and modifier, a coating film of sufficient thickness may not be obtained with one application. In this case, one more application is unavoidably required.

(Means for solving the problem) The present invention should always be able to obtain a coating film of sufficient thickness with one application. It was discovered that good results could be obtained by adding the agent, and the present invention was completed.

HIJ, the method for producing painted formwork plywood of the present invention consists of a compound having a conjugated diene bond (first component) and a vinyl monomer (
A reactive monomer (second component) having a crosslinkable reactive group in its side chain selected from the group consisting of a carboxyl group, an N-methylol group, a grindyl group, a hydroxyl group, a 7-mino group, an amide group, and an acid anhydride. A composition (hereinafter referred to as the coating composition) consisting of a modified synthetic rubber latex consisting of a copolymer with three components), a thermosetting amino resin, a modifier, and a filler is applied to one or both sides of the formwork plywood. After that, it is characterized by heating and converting it into feces.

(Specific means for carrying out the invention) The present invention will be described in detail.

The modified rubber latex used in the present invention is disclosed in Japanese Patent Application No. 60-165938 and Japanese Patent Application No. 6, filed earlier by the present inventors.
It can be produced by the same method as the modified synthetic rubber latex used in the invention described in No. 0-283841.

That is, the first component in producing the modified synthetic rubber latex of the present invention is a compound having a conjugated diene bond, and bucdiene or isoprene is used as the base.

The vinyl monomer (second component) is one that can be copolymerized with the first component and the third component, such as styrene,
Examples include methyl acrylate, methyl methacrylate, and acrylonitrile.

The amount of the compound having a conjugated diene bond (first component) in the modified synthetic rubber latex is 20 to 80% (
% by weight (hereinafter referred to as %) is preferred. The first component is 2
If it is less than 0%, the coating III of the painted formwork plywood manufactured using the latex will become too hard and cracks will easily occur on the coating surface.On the other hand, if it exceeds 80%, the coating of the painted formwork plywood manufactured using the latex will become too hard. This is not preferable because the membrane surface becomes too soft and easily scratched.

Examples of the reactive monomer (third component) having a crosslinkable reactive group in its side chain include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, etc., as monomers having a carboxyl group. -N-methylol acrylamide, N-
Examples include methylolmethacrylamide and their ethers; monomers with glycidyl groups include glycidyl acrylate, glycidyl methacrylate, and acrylic glycidyl ether; monomers with hydroxyl groups include allyl alcohol, 2-hydroxyethyl methacrylate, There are 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, monoallyl ether of polyhydric alcohol, etc. Monomers having an amino group include N,N-dimethylaminoethyl acrylate, vinylpyridine, ter Examples include t-butylaminoethyl methacrylate, and t-butylaminoethyl methacrylate.
include acrylamide, methacrylamide, maleamide, etc., and acid anhydrides include itaconic anhydride, maleic anhydride, etc.

The ratio of the third component in the modified synthetic rubber latex is preferably 0.1 to 20% based on the total amount of the first component and the second component. If it is less than 0.1%, the crosslinking of the modified synthetic rubber latex will be insufficient and a strong coating film will not be obtained on the formwork plywood, and if it exceeds 20%, the stability of the latex during polymerization will be poor. This is because good latex cannot be obtained.

In addition, the solid content concentration in the modified synthetic rubber latex used in the present invention is high, since the amount of water being kneaded is low, cloudiness of the painted formwork plywood (cloudiness is defined as the presence of too much water in the composition) In addition, in the process of heat-pressure curing of the composition to form a coating film, a portion of excessive moisture is locally or generally sealed within the coating film, leaving only that area in a cloudy state. This is a term used to refer to cloudy areas, and cloudy areas are preferable in that they can prevent the acid and alkali resistance of the coating from decreasing.However, modified synthetic rubber latex is usually commercially available with a solid content concentration of 40 to 60%. Therefore, in the present invention, this commercially available product can be used as is.

Next, examples of the heat-curable amino resin (hereinafter simply referred to as amino resin) used in the present invention include urea resin, melamine resin, and co-condensed resin adhesives thereof.

As urea resins, formaldehyde (F) and urea (U
) with a molar ratio of 1.0 to 3.0 as F/U, and as melamine resin, the molar ratio of formaldehyde (F) and melamine (M) as F/M is 2.
．． Those condensed at a ratio of 0 to 3.5 are used. Further, these amino resins are preferably modified using a modifier such as polyvinyl alcohol, carboxymethyl cellulose, or hydroxyethyl cellulose. The reason is that an amino resin with an appropriate viscosity can be obtained by modification, so that when the composition used in the present invention is applied to formwork plywood, a coating film with an appropriate thickness is obtained.

The solid content concentration in the amino resin is preferably 60% or more, and 6
More preferably 0 to 80%. Less than 60% paint Nil
In the process of heating and curing the paint composition, the content of the paint composition increases, and this is undesirable because it tends to cause localized curing defects (commonly known as dust), and the alkali resistance and mortar resistance of those areas decrease. On the other hand, amino resins with solid content concentrations of 80 parts or more are difficult to manufacture and inconvenient to handle.

In the present invention, the -
In the seventh case, the solid content of the amino resin is preferably 50 to 400 parts with respect to 100 parts by weight of the solid content in the modified synthetic rubber latex (hereinafter, parts by weight are referred to as "parts by weight"). More preferably, it is 100 to 300 parts. When the amount of amino resin is higher than the above ratio, the coating film of the resulting painted form plywood becomes too hard, cracks appear on the coating surface, the coating layer becomes brittle, and weather resistance tends to decrease. On the other hand, if the proportion of amino resin is too low, the coating film surface will become too soft and will not be easily scratched (not only will it become difficult to scratch), but the chemical resistance such as acid resistance and alkali resistance of the coating film will deteriorate, and therefore it will not be possible to use concrete mortar. It is not preferable because the coating film performance is not sufficient to withstand the problem.

Examples of the modifier used in the present invention include polyoxoethylene nonyphenyl ether, polyoxoethylene octylphenyl ether, polyoxoethylene dobnorphenyl ether, polyoxyethylene alkyl allyl ether, polyorthone ethylene oleyl ether, and polyoxyethylene oleyl ether. Ethers such as oxyethylene lauryl ether, polyquinoethylene alkylphenyl ether, polyquinoethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene lanolin alcohol ether, polyoxine alkylamino ether, polyoxyethylene distearate, polyoxy Esters such as ethylene lanophosphate, fatty acid jetanolamides or sulfonated products or phosphate compounds of these compounds, dimethylpolysoloxane silicone, methyl silicone, dimethyl silicone, methylhydrogen polysiloxane silicone,
Silicone compounds such as methylphenyl silicone and fluorosolicone, compounds in which the methyl group of dimethylpolynoloxane is converted into α-methylstyrene, α-olefinized compounds, polyetherified compounds, trifluoroalkylated compounds, amidation Examples include mercapto-formed compounds, evoquinated compounds, carboxylated compounds, and polyolefin wax emulsions such as polyethylene wax and polypropylene wax, and one or more of these compounds can be used.

The amount of the modifier added is preferably 0.2 to 10 parts per 100 parts by weight of the total solid content in the synthetic rubber latex and the solid content in the amino resin. If it is less than 0.2 parts, it is not preferable because the alkali resistance of the painted formwork plywood and the releasability between the painted formwork and cement mortar will deteriorate;
It is not preferable to use more than 100 ml of paint, since not only will it not be possible to obtain a strong coating 11, but also the cost will increase, resulting in an economical disadvantage.

There are organic and inorganic fillers, but the fillers preferably used in the present invention are water-insoluble ones, and organic fillers include wood flour and coconut palm, while inorganic fillers include kaolin, talc,
Examples include clay, calcium carbonate, and stone powder, which are used after being ground to a particle size of 200 mesh or less. Incidentally, the use of sterilized powder such as wheat flour is disadvantageous because the viscosity of the coating composition becomes too high.

The amount of filler added varies somewhat depending on the type of filler, but is preferably 20 to 200 parts per 100 parts of the total solid content in the modified synthetic rubber latex and the solid content in the amino resin. If the amount is less than 20 parts, it is not appropriate because a coating film of an appropriate thickness may not be obtained when the composition used in the present invention is applied to formwork plywood.On the other hand, if it exceeds 200 parts, the filler Excessive amount is not preferable because the coating film becomes brittle.

In the present invention, a modified synthetic rubber latex, an amino resin, a modifier, and a filler are mixed at room temperature to form a coated T4 product, but there is no particular restriction on the order in which the above four components are mixed. . For example, after mixing modified synthetic rubber latex, amino resin, and filler, a modifier may be added to the dirt.
It is possible to mix either the modified synthetic rubber latex or the amino resin and the modifier in advance, and then mix these two components and the filler.

Incidentally, in order to obtain a beautiful painted formwork plywood, it is preferable to add a small amount of a known pigment made of titanium or iron oxide to this coating composition. The amount of the pigment added varies depending on the hue of the pigment, but is suitably 1 to 5 parts per 100 parts of the coating composition.

The thus obtained coating composition further contains 1 to 3 parts of a conventionally known curing accelerator for amino resins (hereinafter simply abbreviated as curing accelerator) such as ammonium chloride, ammonium sulfate, ammonium nitrate, etc. per 100 parts of amino resin. It is preferable to add

The coating composition to which the curing accelerator has been added is applied to one or both sides of the formwork plywood as a base material as soon as possible.

Whether to coat one side or both sides depends on the intended use of the manufactured coated form plywood.

The amount of coating composition applied to the plywood formwork is usually 50 to 400 g/rd, preferably 200 to 400 g/rd per surface area of the plywood formwork.
It is 300g/rd. If the coating amount is less than 50g/rt1, a sufficiently thick coating layer will not be formed;
/ n7 or more is not preferable because the coating layer is too thick and the coating composition is wasted, leading to an increase in cost. As the coating method, a known roll coater method is commonly used.

Thus, it is preferable to cure the coating composition applied to the formwork plywood under pressure to obtain a smooth coating surface and also to obtain a strong coating film, so it is usually cured by hot pressing. The material is heat-hardened by hot pressing, hot rolling with heater rolls, etc., but prior to heat-hardening, it is preferable to perform preliminary drying at a temperature lower than the heat-hardening temperature.

In other words, if the paint composition is applied to the formwork plywood and then suddenly hot-pressed, since the paint composition still has fluidity, it will flow out of the formwork plywood and cause an underapplication, resulting in a uniform coating. It is not possible to obtain a continuous coating film, and furthermore, it is not possible to obtain a coating film of an appropriate thickness. Further, the paint composition flowing out from the formwork plywood not only results in loss but also causes staining of equipment such as the press and heater rolls, which is inconvenient.

Pre-drying forms a film on the surface of the coating composition applied to the formwork plywood, and the viscosity of the coating composition also increases significantly, so it is possible to apply the coating to an appropriate thickness without causing the above problems during hot pressing. It is possible to obtain a film. Pre-drying temperature is preferably 40 to 80°C.

At temperatures below 40°C, it takes a long time for the surface of the coating composition to dry and form a film. On the other hand, temperatures exceeding 80° C. are unsuitable because the temperature is too high and the surface of the coating composition may be completely cured during pre-drying. Although the pre-drying time depends on the pre-drying temperature, it is usually carried out for 5 to 30 minutes.

As mentioned above, the coating composition applied to formwork plywood can be heated and cured using a hot press or a heater roll after preliminary drying to obtain coated formwork plywood. ) is more preferable. Even if the formwork plywood has a slight problem with smoothness due to some distortion on the surface, the distortion can be corrected by hot pressure compression, so the surface can be made smooth and a dense coating surface can be obtained. Because it can be done. Heating compression pressure is 10-30K
g/a (-G is appropriate. 10Kg/cJ-G pressure is insufficient, and high pressure exceeding 30g/c4-G will compress the wooden part that is the base material of the painted formwork plywood. As the thickness decreases, it is necessary to increase the thickness in advance, which is economically disadvantageous.The conditions for hot compression are usually 110-130°C for 30-180 seconds.

Since the heater roll rolls at a pressure of approximately 3 Kg/cat-G, the pressure is slightly insufficient to solve the above problem.

In the method using a hot press, it is more preferable to cover the coating film with a plastic film such as a polyester film or a Teflon film and then heat press it, since a mirror surface can be imparted to the coating film surface.

(Effect of the invention) Since the present invention is a method for manufacturing such painted formwork plywood,
Therefore, since the paint used has a lower hardness than conventional acrylic paints and urethane paints and can be cured by heating, the curing time can be significantly shortened, and productivity can be greatly improved. In addition, as for the number of times the paint is applied, whereas conventional acrylic coating T4 and urethane coating T1 require two or three coatings, the present invention allows a coating film of an appropriate thickness to be obtained with one coating. Furthermore, the performance of the coating film was also superior to those using conventional acrylic paints, as shown in Examples and Comparative Examples.

Furthermore, in the present invention, the patent application filed in 1986 by the present inventors
Compared to the method of No. 283841, it is possible to eliminate the coating V of coating t4 on the formwork plywood, so it is also economically advantageous in this respect.

In addition, in the present invention, since the heat-pressing curing method can be used to heat-cure the paint, it is now possible to use low-grade logs that could not previously be used as formwork plywood surface materials because of their tendency to warp. In this respect as well, significant cost reductions can be achieved.

As mentioned above, the painted formwork plywood obtained by the method of the present invention can use less raw materials than conventional ones, has higher production efficiency, and has better performance than that using acrylic paint. , the effect is extremely large.

(Examples and Comparative Examples) The present invention will be specifically explained below using Examples and Comparative Examples.

Example 1 To 60 parts of a urea resin with a solid content of 70% (molar ratio of formaldehyde and urea: 1.8), carboquino-modified styrene-butadiene synthetic rubber latex (butadiene 43%,
51% styrene, 6% acrylic acid, 48% solids) 40
1 part, 0.2 parts of a silicone modifier (Shin-Etsu Silicone KF351, manufactured by Shin-Etsu Chemical ■), and 30 parts of talc (35, manufactured by Nippon Talc (+1)) as a filler were added to prepare a coating composition.

This coating composition is further mixed with 5 parts of a white pigment (0R-650 manufactured by Resino Color Kogyo IL@) and a black pigment (LN-750 manufactured by Resino Color Kogyo 0X) to form a gray pigment, and chloride as a curing accelerator. One part of ammonium was added and applied to only one side of the formwork plywood at a rate of 220 g/n using natural caulk and a reverse coater.

The form plywood coated with the coating composition was then placed in a dryer and pre-dried at a temperature of 60° C. for 10 minutes.

After pre-drying the formwork plywood, the entire surface of the coating is coated with a thickness of 100 mm.
After covering it with a μm unsaturated polyester film (Mylar film manufactured by DuPont, USA), it was heat-pressed for 120 seconds at a temperature of 120°C and a pressure of 10 Kg/cJ・G using a hot press to form a painted mold. Frame metal (manufactured).

The physical properties of the obtained painted formwork plywood are as shown in Tomo-1.

Example 2 50 parts of a urea resin with a solid content of 60% (pol 1. molar ratio of aldehyde and urea 2.0) was mixed with N-methylol-modified styrene-butadiene synthetic comb latex (butanoene 1).
5%, styrene 52%, N-methyl[1-lylacrylamide; 3%, solid content 48%) 50 parts, polyethylene wax 2 parts and clay (Japan No. 50 parts (manufactured by Manufacturer, Inc.) were added to prepare a VJI proboscis.

In addition to this coating composition, 5 pigments (same as in Example 1) were added.
1 part of ammonium chloride as a hardening accelerator was applied to both sides of formwork plywood made of erima wood (a material that easily warps) using a knife coater for 170 min.
It was applied at a rate of g/m.

The form plywood coated with the coating composition was placed in a dryer and pre-dried at a temperature of 50° C. for 15 minutes.

Immediately after pre-drying the formwork plywood, cover the entire surface of the coating with a 188 μm thick unsaturated polyester film (1 m from the east).
As in Example 1, the temperature was 110°C.
C. and a pressure of 15 kg/c+d.G for 60 seconds to produce coated formwork plywood with a smooth surface.

The physical properties of the obtained painted formwork plywood are as shown in Table-1.

Example 3 Glynosyl-modified styrene-butadiene synthetic rubber latex (mole ratio of formaldehyde and melamine: 2.5, molar ratio of formaldehyde and urea: 1.6) was added to 65 parts of a melamine-urea cocondensation resin with a solid content of 65χ. butadiene 45%, styrene 52%, glycidylmequaacrylate 3%, solids content 48%) and 2 parts of the same modifier used in Example 1 and the same modifier used in Example 1 as filler. 40 parts of the same talc as above was added to prepare a coating composition.

In addition to this coating composition, 4 parts of the same pigment also used in Example 1 and 1 part of ammonium chloride as a curing accelerator were added.
270g per side of the formwork plywood.
It was applied at a rate of 100 g.

The form plywood coated with the coating composition was then placed in a dryer and pre-dried at a temperature of 70° C. for 8 minutes.

The pre-dried form plywood was cured by rolling at a temperature of 130°C for 10 seconds using a heater roll made of an endless unsaturated polyester sheet with a thickness of 250 μm, and then placed in the dryer again for 120 minutes. It was dried at ℃ for 10 minutes to produce painted formwork plywood.

The physical properties of the obtained painted formwork plywood are as shown in Table-1.

Comparative Example 1 Various physical properties of painted formwork plywood using a commercially available acrylic paint were measured. The results are shown in Table-1.

As shown in Table 1 in the Examples and Comparative Examples above, the painted form plywood obtained by the present invention had better physical properties than the painted form plywood using conventionally known acrylic paints. .

Comparative Example 2 60 parts of urea resin with a solid content of 70% (molar ratio of formaldehyde and urea 1.8) was added with carboxy-modified styrene-butadiene synthetic rubber latex (43% butadiene,
51% styrene, 6% acrylic acid, 48% solids) 40
and 0.2 parts of a silicone modifier (Shin-Etsu Silicone KF351, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to prepare a coating t1 composition.

To this coating composition, 5 parts of pigment (same as in Example 1) and 1 part of ammonium chloride as a hardening accelerator were added, and coated on only one side of the formwork plywood with natural caulk and a reverse coater at 150 g/m2. It was applied at the rate of

The form plywood coated with the coating composition was then placed in a dryer and pre-dried for 10 minutes at a temperature of 60°C. However, the coated formwork plywood after pre-drying had a problem of a thin coating film, so after applying the above coating composition again at 100 g/rd, pre-drying was carried out under the same conditions as above.

The pre-dried form plywood was covered with a 100 μm thick unsaturated polyester film (Mylar film manufactured by DuPont, USA) over the entire surface of the coating, and then heated using a hot press at a temperature of 120°C and a pressure of 10KFX/cnt.
-G heat-pressing was carried out for 120 seconds to produce formwork plywood.

The physical properties of the obtained painted form plywood were good as shown in Table 1.

In addition, various tests were conducted by the following methods.

1) Pour concrete with the composition shown in the table below into a slag adhesion test form and let it surface at 20°C for 2 days. After curing, remove the formwork and observe the state of peeling. Repeat this operation 10 times.

(Observation items) (1) Degree of slag adhesion (no concrete on the paint film) (2) Ease of peeling of formwork plywood from concrete) 2) Water resistant adhesion test 2 ms intervals on the paint film surface Add the base and set it to 100.
48 test pieces cut into squares (10 squares each vertically and horizontally)
After soaking in water for a period of time, the water on the paint surface is thoroughly wiped off, and after pasting packing tape on the coating surface, this is peeled off and the surfaces of the coating film and the packing tape are observed.

3) Blocking test A test piece cut into 30cm squares was cut with the illumination side and the non-coated side pressed together, a load of 20kg was applied to this, and the sample was left at 20°C for 48 hours, then the load was removed and the coated side Admire the blocking of the child.

4) Cold and heat repeated test (B test) According to JAS special plywood test method.

5) Planar tensile test JAs’4. According to the test method for special plywood.

6) Alkali resistance test Compliant with JAS special plywood test method. (20% sodium hydroxide solution i8 instead of 1% sodium carbonate solution)
Use tej. ) 7) Convex (According to the test method of JAS special combination (convex). (10% formic acid aqueous solution was used instead of 5% white acetic acid aqueous solution.) Table -1

Claims (1)

[Claims] 1) A compound having a conjugated diene bond (first component), a vinyl monomer (second component), and a carboxyl group, an N-methylol group, a glycidyl group, a hydroxyl group, an amino group, an amide group, and an acid anhydride. A modified synthetic rubber latex made of a copolymer with a reactive monomer (third component) having a crosslinkable reactive group in its side chain selected from the group consisting of a thermosetting amino resin, a filler, and a modifier. 1. A method for producing painted form plywood, which comprises applying a composition on one or both sides of form plywood and then heating and curing the composition. 2) The method for producing painted formwork plywood according to claim 1, wherein the compound having a conjugated diene bond is butadiene or isoprene. 3) The ratio of the first component to the second component is 20 to 80% by weight of the first component with respect to the total amount thereof, and the ratio of the third component is 0 with respect to the total amount of the first component and the second component. .1-20% by weight
A method for manufacturing painted formwork plywood according to claim 1 or 2. 4) The method for producing coated form plywood according to claim 1, 2 or 3, wherein the heat-curable amino resin is a urea resin, a melamine resin, or any one of these co-condensed resins. 5) Solid content concentration in heat-curable amino resin is 60% by weight
The method for manufacturing painted formwork plywood according to claim 4, which is as described above. 6) The ratio of the modified synthetic rubber latex to the heat-curable amino resin is such that the solid content in the heat-curable amino resin is 50 to 40 parts by weight per 100 parts by weight of the solid content in the modified synthetic rubber latex.
The method for producing painted form plywood according to claim 1 selected from claims 1 to 5, wherein the amount is 0 parts by weight. 7) The proportion of the modifier is 0.2 to 10% by weight based on 100 parts by weight of the total solid content in the synthetic rubber latex and the solid content in the heat-curable amino resin. 1
The method for manufacturing painted formwork plywood according to item 1 selected from items 6 to 6. 8) The ratio of the filler is the total amount of solid content in the modified synthetic rubber latex and solid content in the heat-curable amino resin: 100
The method for manufacturing painted form plywood according to claim 1 selected from claims 1 to 7, wherein the amount is 20 to 200 parts by weight.