JP2009084467A - Adhesive composition suitable for two-part separate coating use, and method for producing laminated form using the same, and the resultant laminated form - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition expressing high adhesive performance even if no premixing is conducted on an adherend in its two-part separate coating operation, to provide a method for producing a laminated form using the composition, and to provide the resultant laminated form. <P>SOLUTION: The adhesive composition comprises 100 pts.wt. of the main agent based on a resorcinolic resin and 55-120 pts.wt. of a curing agent with its curing component consisting of a phenolic resin 1.6-2.4 in the molar ratio of formaldehyde to phenol and 100-500 in the average molecular weight. The laminated form is obtained by making a two-part separate coating of this adhesive composition. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a resorcinol-based adhesive composition that can exhibit excellent adhesive performance without performing preliminary mixing on an adherend during two-component fractional coating, a method for producing a laminate using the resorcinol-based adhesive composition, and a laminate.

  Resorcinol-based adhesives are highly durable and are used in the manufacture of laminated wood products such as laminated wood. Mixing paraformaldehyde, fillers, etc., with the main component mainly composed of resorcinol-based resins It is a two-component adhesive that cures by blending the cured agent. Although water-based polymer-isocyanate adhesives that do not use formaldehyde are also used in the manufacture of laminated wood, even when resorcinol adhesives are used, the highest grade regarding formaldehyde emission can be obtained. For some applications, resorcinol-based adhesives still occupy an important position in the production of laminated materials, such as the limited use of resorcinol-based adhesives. Disadvantages of such two-component adhesives include time and labor for weighing and mixing, need to be used within a predetermined time after mixing, loss of adhesive occurs, and labor for cleaning mixing and coating devices For example.

  When manufacturing a wood laminate product using a resorcinol-based adhesive, a method in which an adhesive is applied as a ramen to a laminator as an adherend, and then laminated and pressed is used. However, when applying the adhesive to the laminar, it is difficult to accurately discharge the adhesive only while the laminator passes through the coating device, so that the adhesive protrudes from the laminator at least immediately before and after the laminar passes. Was inevitable. Therefore, it was considered to collect the adhesive that protruded from the laminar and reapply it, but not so much adhesive was collected, so the problem was that it stagnated in the piping etc. during recovery and hardened was there.

For such a problem, Patent Document 1 proposes a coating apparatus capable of recovering both components by separately applying the main agent and the curing agent to the adherend and mixing them on the adherend. ing. However, in such a method, since the main agent and the curing agent are not sufficiently mixed on the adherend, it is inevitable that the adhesion performance is lowered as compared with the case where they are mixed and used in advance. In order to eliminate the drawbacks in Patent Document 1, in Patent Document 2, a main agent and a curing agent are separately applied to an adherend, and then an adhesive is premixed on the adherend by a method such as air spraying. Has been proposed. However, it is necessary to newly install a device for premixing, or the adhesive is sufficiently mixed on the adherend, and the adhesive is unevenly distributed on the adherend, or the adherend is preliminarily mixed. Therefore, it was necessary to finely adjust the premixing device in order to prevent the adhesive from protruding from.
Patent Document 3 discloses a method of obtaining a wood laminate by separately applying a first liquid obtained by mixing a main agent and a curing agent and a second liquid composed of a curing accelerator. The invention was made for the purpose of improving curability and shortening the pressing time. However, since the mixture of the main agent and the curing agent is used as the first liquid, the adhesive protruding from the laminator is recovered. Cannot be reused.
JP 59-82971 A JP-A-8-197504 JP-A-9-11403

  As described above, in the two-component fractional application method, there are problems in that the adhesive performance is lower than in the case of mixing and using in advance, or that additional installation of devices and fine adjustment are required. The present invention has been made in view of such problems, and an adhesive composition that can exhibit excellent adhesive performance without performing premixing on an adherend during two-component fractional application, using the same It is an object of the present invention to provide a manufactured laminate and a method for manufacturing the laminate.

  This invention is an adhesive composition which consists of 55-120 weight part of hardening | curing agents which use a phenol-type resin as a hardening component with respect to 100 weight part of the main ingredients which have a resorcinol-type resin as a main component. The molar ratio (F / P) of formaldehyde to phenol in the phenolic resin is preferably 1.6 to 2.4, and the average molecular weight of the phenolic resin is preferably 100 to 500. Another invention is a method for producing a laminate, characterized in that the main component and the curing agent of the adhesive composition are separately applied to an adherend, and the laminate is produced using the adhesive composition. .

  The adhesive composition comprising the present invention and the method for producing a laminate using the same enable two-component fractional application, so there is no need to weigh and mix the adhesive, and the protruding main agent and curing agent are collected respectively. Since it can be reused, there is very little loss and the coating device can be easily cleaned. Further, unlike the conventional two-component fractional application method, the adhesive performance does not deteriorate, so that a high-quality laminate can be produced, and since there is no need for premixing, it can be used without installing a premixing device. Therefore, it is particularly useful for producing laminated timber.

  The adhesive composition of the present invention comprises a main agent mainly composed of a resorcinol resin and a curing agent mainly composed of a phenol resin. The resorcinol resin is a resin obtained by reacting resorcinol alone or a part of resorcinol with phenols such as phenol, cresol, xylenol, tannin, lignin, and metaaminophenol, and formaldehyde.

  The phenolic resin is a resin obtained by reacting formaldehyde with phenol alone or a part of the phenol replaced with phenols such as resorcinol, cresol, xylenol, tannin, lignin, and metaaminophenol. Phenolic resins are also used as the main agent of adhesives, but phenolic resins used as the curing agent of the present invention are characterized by a lower degree of polymerization and a lower molecular weight than those. Specifically, it is preferable for the present invention that F / P is 1.6 to 2.4 and the average molecular weight is 100 to 500. The formaldehyde content of the curing agent is preferably 5 to 25%.

  When the phenolic resin is used as a curing component for the resorcinol resin, the reason why excellent adhesion performance can be obtained without premixing is not clear, but the ratio of the main agent to the curing agent is close to 1: 1. It is speculated that this is one factor. In other words, when paraformaldehyde is used as a curing agent, the amount used relative to 100 parts by weight of the main agent is mostly 50 parts by weight or less, and the amount used is smaller than that of the main agent. Then, even if there is a sufficient amount of the curing component stoichiometrically, it cannot be sufficiently contacted with the main agent without premixing, and as a result, it is expected that the curing does not proceed sufficiently. On the other hand, in the present invention, the use amount of the curing agent is 55 to 120 parts by weight, preferably 80 to 100 parts by weight, based on 100 parts by weight of the main agent. Since there are many opportunities for contact between the main agent and the curing agent, curing proceeds sufficiently, and it is expected that excellent adhesion performance is obtained.

  In addition, even when using the paraformaldehyde as a hardening | curing agent, the present inventors examined whether the same effect could be obtained if the use ratio with the main agent was close to 1: 1, but sufficient adhesion performance was obtained. I couldn't. When the amount of paraformaldehyde was simply increased, the amount of formaldehyde emitted from the obtained laminate was significantly increased, which was not suitable for use. Moreover, when the amount as a hardening | curing agent was increased by increasing water, a filler, and a thickener without increasing the amount of paraformaldehyde, sufficient adhesive performance was not obtained without preliminary mixing. Accordingly, any curing agent may be used as long as the ratio of the main agent to the curing agent is close to 1: 1.

  The curing agent of the present invention includes, in addition to the phenolic resin as a curing component, fillers such as wood flour, coconut shell flour, walnut shell flour, wheat flour, soybean flour, rice flour, calcium carbonate, zeolite, clay, and anhydrous silica. And thickeners such as methylcellulose, polyethylene oxide, carboxymethylcellulose, polyvinyl alcohol, xanthan gum and the like can be blended. With these, the viscosity, thixotropy, filling properties, etc. of the curing agent can be controlled, filling the depressions on the surface of the adherend, preventing excessive suction on the adherend, and improving wettability to the adherend. It is possible to improve the coating suitability.

  The resorcinol-based adhesive of the present invention can be used in various fields in the same manner as ordinary resorcinol-based adhesives, but the most remarkable feature is the production of a laminate by two-component fractional coating. By separately applying the main agent and the curing agent to the adherend and laminating and pressing the adherend without premixing, a laminate having excellent adhesion performance can be obtained. Moreover, since the main agent and the curing agent can be recovered and reused, the loss of the adhesive can be reduced. Further, since the main agent and the curing agent are mixed only on the adherend, the application and recovery device can be easily cleaned.

  Hereinafter, based on an Example, this invention is demonstrated more concretely. Of course, the present invention is not limited to the embodiments.

Method for Producing Phenolic Resin 1 216 parts by weight of 37% formaldehyde aqueous solution and 188 parts by weight of phenol were charged into a reaction vessel equipped with a stirrer, thermometer and cooling pipe (F / P: 2.0), and 49% caustic soda as a reaction catalyst. After charging 2.8 parts by weight, the mixture was heated to 80 ° C., reacted at 80 ° C. for 60 minutes, and then cooled to obtain a phenol resin. The average molecular weight by GPC was 200. Phenol resin 1 (formaldehyde content 10%) was obtained by adding 5.9 parts by weight of coconut shell powder to the phenolic resin and adjusting the viscosity to 1 Pa · s / 23 ° C. by adding a thickener.

Method for Producing Formaldehyde Curing Agent 1 By mixing 600 parts by weight of a 37% formaldehyde aqueous solution, 200 parts by weight of water and 150 parts by weight of coconut shell powder, adding a thickener and adjusting the viscosity to 1 Pa · s / 23 ° C. A formaldehyde curing agent 1 was obtained.

Example 1
PRX-265A (trade name, manufactured by Aika Kogyo Co., Ltd.) mainly composed of resorcinol-based resin as a main ingredient on a cypress laminar (length: 2860 mm, width: 110 mm, thickness: 22 mm) so that the coating amount is 150 g / m ^2. The noodles were then applied, and then, the phenol resin 1 was applied as a curing agent to the application amount of 120 g / m ² . 4 sheets of laminator coated with adhesive and 1 sheet of laminated laminar without applying adhesive are used to form 5 sheets (5 ply), applying high frequency using high frequency press with 50kW output A test specimen was prepared by pressing for 8 minutes at 1 MPa and curing for 7 days, and evaluation was performed by the following method.

Test Method Based on the JAS standard for structural laminated wood, a dipping test (use environment 1), a boil-off test (use environment 1), and a formaldehyde emission test were performed. For the immersion peeling test and the boiling boiling test, those that conformed to the standards were evaluated as “good”, and those that did not conform were evaluated as “poor”. Regarding the amount of formaldehyde diffused, a value of 0.3 mg / L or less was evaluated as ◯, and a value exceeding 0.3 mg / L was evaluated as ×.

Example 2 and Comparative Examples 1 and 2
In Example 1, it carried out like Example 1 except having changed the application quantity of PRX-265A and the phenol resin 1 as described in Table 1.
Comparative Examples 3 and 4
Example 1 was carried out in the same manner as Example 1 except that formaldehyde curing agent 1 was used instead of phenol resin 1 as the curing agent, and the coating amount was changed as described in Table 1.

  Each example gave good results in adhesion performance and formaldehyde emission. In Comparative Examples 1 to 4, at least one of adhesion performance and formaldehyde emission was poor. Therefore, it has been found that good results can be obtained only when the main component mainly composed of resorcinol resin and the curing agent mainly composed of phenol resin are used and the blending ratio of both is specific.

Claims (5)

  The adhesive composition which consists of 55-120 weight part of hardening | curing agents which use a phenol-type resin as a hardening component with respect to 100 weight part of main ingredients which have a resorcinol-type resin as a main component.   The adhesive composition according to claim 1, wherein the phenolic resin has a molar ratio of formaldehyde to phenol of 1.6 to 2.4.   The adhesive composition according to claim 1 or 2, wherein the phenolic resin has an average molecular weight of 100 to 500.   The manufacturing method of the laminated body characterized by fractionally apply | coating the main ingredient and hardening | curing agent of the adhesive composition in any one of Claims 1-3 to a to-be-adhered material.   The laminated body manufactured using the adhesive composition in any one of Claims 1-3.