JPH0433242B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for manufacturing flame-retardant plywood with excellent adhesive performance, which is used for interior materials of general buildings, ship bulkheads, and the like. (Structure of conventional technology and its problems) Conventionally, in order to manufacture flame-retardant plywood with a high degree of adhesiveness, phenolic resin is used as an adhesive, and veneers are laminated in the presence of a flame retardant and heated. Pressure bonding is commonly used, but the method published by Morikita Publishing Co., Ltd., “Practical Wood Processing Complete Book Volume 9 (Special Plywood)”
As stated on page 175, flame retardants significantly reduce the adhesive strength of phenolic resins, making it difficult to produce flame-retardant plywood with high adhesive properties, especially water-resistant adhesive properties. Furthermore, this type of adhesive is easily affected by the wood species and moisture content of the veneer used, and there is a problem in that it severely limits the production of flame-retardant plywood. On the other hand, when manufacturing flame-retardant plywood using melamine or a known amino resin aqueous solution containing melamine resin as an adhesive, the water resistance is weak and the flame-retardant plywood is classified as Japanese Agricultural Standard (hereinafter referred to as JAS) Class 1. It is not possible to manufacture plywood that passes the standard, and only plywood that falls under category 2 plywood can be obtained. (Objective of the invention) The present invention aims to eliminate the above-mentioned problems, and provides a method for manufacturing flame-retardant plywood that has sufficient flame-retardant performance as specified by JAS and has high adhesive performance that falls under JAS special classification. This is what we provide. (Structure of the Invention) In order to achieve the above object, the method for producing flame-retardant plywood of the present invention uses a solid content of an aqueous solution of a co-condensate of phenol and an amino resin as an adhesive for laminating and bonding a plurality of veneers. Using an adhesive made by adding 1 to 50 parts by weight of resorcin resin in terms of solid content per 100 parts by weight, and further adding an appropriate amount of filler as necessary, it is difficult to attach laminated veneers through this adhesive. By bonding under heat and pressure in the presence of a combustible material, it is possible to manufacture flame-retardant plywood with a high degree of water resistance that passes the continuous boiling test stipulated by the JAS Special Class. In the method of the present invention, the aqueous solution of a cocondensate of phenol and an amino resin used is an initial condensate or an initial condensate such as a phenol/melamine/formaldehyde cocondensate or a phenol/melamine/urea/formaldehyde cocondensate. A typical example is an aqueous solution, and other examples include phenol and
Formaldehyde initial condensate, phenol/melamine/formaldehyde initial condensate, melamine/
One or two urea/formaldehyde initial condensates
An aqueous solution of a mixture of more than one species is used. Part or all of the phenol constituting such an aqueous solution may be replaced with phenols such as cresol and xylenol. In addition to the above-mentioned melamine and urea, the amino resin components include thiourea, benzoguanamine,
One or more types of acetoguanamine and the like can be used. Depending on the application, a part of the co-condensate of phenol and amino resin may be replaced with a phenol resin or an amino resin. As the resorcin resin, 0.3 per mol of resorcin or a mixture of resorcin and phenol is used.
It is a reaction product with ~1.5 mol of formaldehyde, and it is also possible to replace part or all of the phenol used in combination with resorcinol with phenols such as cresol and xylenol. Furthermore, a part of resorcinol can be replaced with 5-methyl resorcinol, 5-ethyl resorcinol, 4.5 dimethyl resorcinol, and other resorcinol derivatives alone or in mixtures. Flame retardants include inorganic and/or organic phosphorus salts such as diammonium phosphate, monoammonium phosphate, guanidine phosphate, and melamine phosphate; polyphosphates such as ammonium polyphosphate and polyphosphate carbamate; ammonium chloride, and bromide. Halogen compounds such as ammonium, calcium chloride, and calcium bromide: Sulfamate salts such as ammonium sulfamate, sulfamate amide, sulfamate imide, and sulfamate urea: Flame retardants such as boric acid and borates such as borax are common. However, other substances such as aluminum sulfate/potassium, aluminum sulfate/sodium, etc.: tin, tungsten, titanium,
Metal salt compounds such as antimony and magnesium:
Flame retardants such as alkyl phosphate esters such as methyl phosphate and ethyl phosphate; phenyl phosphate esters such as cresyl phosphate; and aminoalkyl phosphate esters such as aminomethyl phosphate and aminoethyl phosphate are also used. . These flame retardants may be used alone or in combination of two or more. When manufacturing flame retardant plywood, the purpose of the present invention is to pass the JAS special adhesive performance and flame retardant standards, and it is possible to use a veneer that has been pre-impregnated with a flame retardant. It is also possible to add a flame retardant to the veneer, apply this adhesive to the veneer, and then laminate the veneer and bond it under heat and pressure. It is also effective to laminate flame-retardant-treated veneers and untreated veneers using a flame-retardant-added adhesive. In the production of ordinary flame retardant plywood, flame retardants are
Either use an aqueous solution with a concentration of 20 to 50% and immerse the veneer in this aqueous solution, or mix 15 to 30 parts by weight of a flame retardant to 100 parts by weight of the adhesive to fully satisfy the fireproof performance. The one that was made is used. However, in the formulation of adhesives using phenolic resin, if 15 parts by weight or more of flame retardant is present, there are restrictions on the amount of adhesive applied, heat and pressure conditions, wood species of the veneer, etc., resulting in a high degree of water resistance. It has been difficult to manufacture economical flame-retardant plywood with good productivity and high productivity. In the present invention, there are no particular restrictions on the amount of flame retardant added, but in order to satisfy the JAS special adhesive performance and flame retardancy, it is necessary to add 15 to 30 parts by weight of flame retardant to 100 parts by weight of adhesive. It is appropriate to mix the parts. In carrying out the present invention, other components blended into the adhesive include thickeners, extenders, dispersants, etc., and an acidic catalyst such as ammonium chloride is used as a catalyst to accelerate the curing reaction. be able to. Wheat flour, barley flour, rice flour, wood flour, blood powder, etc. are used as the thickeners and extenders added to the adhesive, and 100 parts by weight of an aqueous solution of a co-condensate of phenol and amino resin is added to the entire adhesive. It is blended in an amount of 10 to 60 parts by weight, preferably 15 to 40 parts by weight. As the dispersant, for example, one or more of polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, nonionic surfactants, anionic surfactants, and cationic surfactants can be used in combination. One of the features of the production of plywood according to the present invention is that it is possible to produce flame-retardant plywood with a high degree of water resistance even when using veneers with high moisture content and hard-to-bond wood veneers containing a large amount of resin (tar). Also, the moisture content is 15~
Even if it is a 30% veneer, it is also possible to use a veneer made of hard-to-bond wood such as avitone, kluin, capor, maple, beech, etc. The production of plywood in the present invention can be carried out by the same method as that used for conventionally known amino resin adhesives. That is, the adhesive size liquid according to the present invention described above is applied to the adhesive surface of a veneer prepared in advance using an adhesive coating device such as a spreader roll or a curtain flow coater.
After coating the plywood at a rate of 150 to 200 g/m ² , the layers are laminated and cold-pressed at room temperature for 15 to 60 minutes at a pressure of 8 to 15 kg/cm ² .
15 to 1 mm of plywood thickness using a hot press maintained at a temperature of 110 to 140°C under pressure of 15 Kg/ ^cm2
Plywood is produced by heat pressing at a rate of 50 seconds to harden the adhesive. (Description of Examples) Next, specific examples of the present invention will be shown. Example 1 After impregnating and injecting an organic phosphate flame retardant into a 1.5 mm thick lauan veneer and 1 3.0 mm thick lauan veneer, these veneers were hydrated using a hot air circulation dryer. Dry to a rate of 10%. Next, a phenol-melamine cocondensation resin (for example, PG9161- manufactured by Dainippon Ink and Chemicals Co., Ltd.)
100 parts (solid content 55% cps), 15 parts flour, 5 parts water
After mixing 5 parts of resorcinol resin (for example, MD526 manufactured by Dainippon Ink Chemical Co., Ltd.), these are thoroughly mixed to form an adhesive, and this adhesive is used to bond each of the flame-retardant veneers. The thicker veneer was applied to the front and back sides, and the thicker veneer was placed in the center, and the thinner veneers were placed on the front and back sides to form a 6 mm thick plywood. The amount of flame retardant impregnated into the veneer is determined by the solid content.
320 g/m ² (converted to a thickness of 6 mm), and the amount of adhesive applied is 100 g/m ² (per adhesive layer) in terms of solid content. Next, the laminated veneer was inserted into a hot press and hot-pressed at 120°C for 8 kg/cm ² for 3 minutes.
Flame retardant plywood was obtained. The flame retardant plywood obtained in this way is rated as ``Class 3 flame retardant'' as stipulated in JISA1321 (Flame retardant test method for building interior materials and construction methods), ``Flame retardant class 3'' as stipulated in JISA1321 (Flame retardant test method for building interior materials and construction methods), It complied with both the Japanese Agricultural and Forestry Standards for flame-retardant plywood. Furthermore, the adhesion between the flame-retardant treated veneers passed the shear strength of 7 kg/cm ² or higher, which is the specified value of the special continuous boiling test specified in the Japanese Agricultural Standards for structural plywood. Comparative Example 1 A melamine resin adhesive was applied to a flame-retardant treated veneer board procured according to Example 1, and the sheets were bonded together in the same manner as in Example 1, and then heated at 120°C using a hot press.
A flame-retardant plywood with a thickness of 6 mm was obtained by hot pressing under the conditions of -8 Kg/cm ² -6 minutes. Although this flame-retardant plywood satisfied the regulations described in Sections 1 to 2 in Example 1, it did not pass the repeated boiling test of JAS Class 1 as well as the continuous boiling test in terms of adhesion. Comparative Example 2 A phenolic resin adhesive was applied to a flame-retardant treated veneer board procured according to Example 1, and the veneer was bonded together, then heated at 140°C at 10Kg/cm ² -9 using a hot press.
A flame-retardant plywood with a thickness of 6 mm was obtained by hot pressing for 1 minute. This flame-retardant plywood complied with the regulations described in the sections 1 to 2 in Example 1, and also passed the repeated boiling test, but failed the continuous boiling test. Next, the adhesive performance of Example 1 and Comparative Examples 1 and 2 will be shown.

[Table] Example 2 Five Kapol veneers with a thickness of 2.0 mm and four Kapor veneers with a thickness of 3.0 mm were impregnated with an organic phosphoric acid flame retardant, and after injection, these veneers were dried in a hot air circulation dryer. was dried to a moisture content of 10%. Next, the adhesive used in Example 1 was applied to these flame-retardant veneers, and then 2.0 mm thick veneers and 3.0 mm thick veneers were alternately laminated and temporarily bonded to increase the thickness. A 22.0 mm 9-ply temporarily bonded plywood was constructed. The amount of flame retardant impregnated into this temporarily bonded plywood was 1170 g/m ² in terms of solid content. Next, the temporarily bonded plywood was inserted into a hot press and hot-pressed and bonded under conditions of 120° C. and 8 kg/cm ² for 15 minutes to obtain a flame-retardant plywood with a thickness of 22 mm. The flame-retardant plywood thus obtained passed the standard fire test stipulated in the 1974 Convention for the Safety of Life at Sea, making it suitable for Class B bulkheads for ships, and also passed the continuous boiling test for adhesion. Comparative Example 3 After applying a phenolic resin adhesive to a flame-retardant treated veneer board procured according to Example 2 and bonding it together,
Using a hot press, hot pressing was carried out under the conditions of 140° C. and 10 kg/cm ² for 33 minutes to obtain a flame-retardant plywood with a thickness of 22 mm. When this flame-retardant plywood was subjected to a standard fire test,
During heating, the veneer fell off and the flame penetrated, resulting in a failure. In addition, it also failed the repeated boiling test. Next, the adhesive performance of Example 2 and Comparative Example 3 will be shown.

[Table] Example 3 100 parts of phenol-melamine cocondensation resin (PG9161 manufactured by Dainippon Ink & Chemicals Co., Ltd.), 10 parts of wheat flour
10 parts of water, 5 parts of phenol/alkyl resorcinol/formaldehyde resin (MD4801 manufactured by Dainippon Ink & Chemicals Co., Ltd.), and 30 parts of polyphosphate flame retardant is mixed into 100 parts of adhesive. do. Using this flame retardant-containing adhesive, the adhesive was applied to both sides of a 3.0 mm thick flame retardant treated lauan veneer procured according to Example 1, and the 1.5 mm thick untreated lauan veneer was applied to the front and back sides. Arrange and stack the boards. Next, this laminated veneer plate formed to a thickness of 6.0 mm was inserted into a hot press and hot-pressed at 120° C. for 8 kg/cm ² for 3 minutes to obtain a flame-retardant plywood having a thickness of 6 mm. The flame retardant plywood thus obtained is JISA1321,
It passed both the Japanese Agricultural and Forestry Standards for flame retardant materials and flame retardant plywood based on the Ministry of Construction Notification No. 1231 and the Fire Retardant Material Certification Guidelines. Furthermore, the adhesion between the untreated veneer of the front and back plates and the flame-retardant treated veneer of the core plate passed the JAS special continuous boiling test for structural plywood. Comparative Example 4 30 parts of a polyphosphate flame retardant is mixed into 100 parts of a phenolic resin adhesive. Using this flame retardant-containing adhesive, the flame retardant treated and untreated boards procured according to Example 3 were bonded together, and then heated at 140°C - 10Kg/cm ² -9 using a hot press.
A flame-retardant plywood with a thickness of 6 mm was obtained by hot pressing for 1 minute. This flame-retardant plywood complies with the regulations described in Sections ~ shown in Example 3, and is subject to repeated boiling tests (JAS Class 1).
It passed the test, but failed the continuous boiling test.

[Table] (Example 4) Ammonium bromide flame retardant was added to each of a 1.5 mm thick Chinese veneer and a 3.0 mm thick lauan veneer in an amount of 300 g/m ² (in terms of solid content) (6 mm thick). After injecting the veneers at the same rate, these veneers were dried to a moisture content of 10% using a hot air circulation dryer. Next, 10 parts of soybean powder and 5 parts of water were mixed with 100 parts of phenol/melamine cocondensation resin (PG9161, manufactured by Dainippon Ink and Chemicals Co., Ltd.), and then resorcinol resin (manufactured by Dainippon Ink and Chemicals, Ltd.) was added.
MD526) 25 parts of a borate flame retardant was mixed into 100 parts of the adhesive, which was thoroughly mixed with 10 parts of the adhesive. This flame retardant-containing adhesive was applied to both the front and back surfaces of a lauan veneer at a rate of 100 g/m ² in terms of solid content, and Chinese veneers were placed on both sides and laminated. Next, insert the laminated veneer into the hot press.
Heat pressed under the conditions of 120℃ - 8Kg/cm ² -3 minutes, 6mm
A thick flame retardant plywood was obtained. The thus obtained flame-retardant plywood passed the regulations described in the sections 1 to 2 in Example 1, and also passed both continuous boiling and repeated boiling for adhesive properties. (Comparative Example 5) 25 parts of a borate flame retardant was mixed into 100 parts of a phenolic resin adhesive. Using this flame retardant-containing adhesive, flame-retardant treated veneers procured according to Example 4 were bonded together and hot-pressed using a hot press for 9 minutes at 140°C and 10 kg/cm ² to form a flame-retardant sheet with a thickness of 6 mm. I got plywood. This flame-retardant plywood complied with the regulations described in Sections 1 to 3 of Example 1 and passed the repeated boiling test, but failed the continuous boiling test.

[Table] (Example 5) Phenol/melamine/urea/cocondensation resin 100
30 parts of a sulfamate-based flame retardant was mixed into 100 parts of an adhesive prepared by thoroughly mixing 10 parts of wheat flour, 5 parts of soybean flour, 10 parts of water, and 15 parts of resorcinol/phenol cocondensation resin. Next, a 3 mm thick lauan veneer was impregnated with a mixed flame retardant of borax and boric acid at a rate of 300 g/m ² in terms of solid content, and then heated in a hot air circulation dryer to achieve a moisture content of 10.
dried to %. The above adhesive was applied to both sides of this 3mm veneer at a rate of 100g/ ^m2 in terms of solid content, and the thickness was 1.5mm on both sides.
Laminated with untreated Chinese veneers of
A flame retardant plywood with a thickness of 6 mm was obtained by hot pressing at 120° C. for 8 kg/cm ² for 3 minutes. Thus, the obtained flame-retardant plywood passed the regulations described in the sections 1 to 2 in Example 1, and also passed both continuous boiling and repeated boiling for adhesive properties. (Comparative Example 6) 30 parts of a sulfamate-based flame retardant was mixed into 100 parts of a phenolic adhesive, and this flame-retardant-containing adhesive was applied to both sides of a flame-retardant treated veneer procured according to Example 5. After coating, untreated Chinese veneers with a thickness of 1.5 mm were placed on the front and back sides and laminated. Next, this laminated veneer plate formed to a thickness of 6.0 mm was inserted into a hot press and hot pressed at 140° C. for 9 minutes at 10 kg/cm ² to obtain a flame-retardant plywood sheet with a thickness of 6 mm. This flame-retardant plywood complied with the regulations described in Sections 1 to 3 of Example 1 and passed the repeated boiling test, but failed the continuous boiling test.

[Table] (Example 6) 100 parts of phenol-melamine cocondensation resin (PG9161 manufactured by Dainippon Ink Chemical Co., Ltd.), 10 parts of wheat flour, 5 parts of soybean flour, 10 parts of water, resorcinol resin (Dainippon Ink Chemical Co., Ltd.) MD526 manufactured by Kogyo Co., Ltd.)
15 parts of sulfamate flame retardant and 15 parts of borate flame retardant to 100 parts of adhesive thoroughly mixed.
part was mixed in. Next, the above adhesive was applied to both sides of a 3 mm thick untreated lauan veneer at a rate of 120 g/m ² in terms of solid content, and 1.5 mm thick untreated Chinese veneers were placed on the front and back sides and laminated. did. Next, this laminated veneer plate formed to a thickness of 6.0 mm was inserted into a hot press and hot-pressed at 120° C. for 8 kg/cm ² for 3 minutes to obtain a flame-retardant plywood having a thickness of 6 mm. The thus obtained flame-retardant plywood passed the regulations described in the sections 1 to 2 in Example 1, and also passed both continuous boiling and repeated boiling for adhesive properties. (Comparative Example 7) 15 parts of a sulfamate-based flame retardant and 15 parts of a borate-based flame retardant were mixed into 100 parts of a phenolic resin adhesive. Using this flame retardant-containing adhesive, it is applied to both sides of untreated veneer boards procured according to Example 6, and untreated Chinese veneers with a thickness of 1.5 mm are arranged on the front and back sides and laminated. Next, this laminated veneer plate formed to a thickness of 6.0 mm was inserted into a hot press and hot pressed at 140° C. for 9 minutes at 10 kg/cm ² to obtain a flame-retardant plywood sheet with a thickness of 6 mm. This flame-retardant plywood complied with the regulations described in Sections 1 to 3 of Example 1 and passed the repeated boiling test, but failed the continuous boiling test due to insufficient shear strength.

[Table] (Effects of the invention) As described above, according to the method for producing flame-retardant plywood of the present invention, 100 parts by weight of an aqueous solution of a co-condensate of phenol and amino resin is used as an adhesive between veneers. In contrast, the laminated veneer is bonded under heat and pressure using an adhesive prepared by adding 1 to 50 parts by weight of resorcin resin in terms of solid content, and further adding and adjusting an appropriate amount of a filler as necessary. Therefore, it is easy to produce flame-retardant plywood with high water resistance and adhesive performance that passes the continuous boiling test of the JAS structural plywood special class because the heat-pressure conditions are relaxed and the adhesion is less inhibited by flame retardants. It can be manufactured in

Claims (1)

[Scope of Claims] 1. A method for producing flame-retardant plywood by bonding a plurality of flame-retardant treated veneers or by laminating and bonding veneers without flame-retardant treatment using a flame retardant-containing adhesive. As an adhesive, 1 to 50 parts by weight of resorcinol resin is added in terms of solid content per 100 parts by weight of solid content of an aqueous solution of a cocondensate of phenol and amino resin, and an appropriate amount of filler is added as necessary. A method for producing flame-retardant plywood, which comprises bonding laminated veneers under heat and pressure using a prepared adhesive. 2 The resorcin resin is 0.3 to 1.5 per mole of resorcin or a mixture of resorcin and phenol.
2. The method for producing a flame-retardant plywood according to claim 1, characterized in that the flame-retardant plywood is reacted with molar amounts of formaldehyde. 3. The method for producing a flame-retardant plywood according to claim 1 or 2, characterized in that part of the resorcinol is replaced with a single resorcinol derivative or a mixture thereof.