JPH03170580A - Adhesive and production of composite panel by using the same - Google Patents

Abstract

PURPOSE:To obtain a sprayable adhesive excellent in adhesiveness to a molded panel of a thermoplastic polyolefin resin by compounding a base based on a thermoplastic polyester polyurethane resin with specified curing agent. CONSTITUTION:This adhesive is prepared from a base based on a thermoplastic polyester urethane resin (e.g. Pandex T5210, a product of Dainippon Ink), an active isocyanato-containing urethane prepolymer obtained by reacting a hydrogenated hydroxyl-terminated polybutadiene glycol with a polyisocyanate (e.g. diphenylmethane diisocyanate) and a curing agent containing a polyisocyanate (e.g. dipenylmethane diisocyanate).

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to an adhesive useful for bonding a foam to a shaped board made of a polyolefin thermoplastic resin, and a composite panel using the same. Relating to a method of manufacturing.

(Prior art) Used as interior wall materials for vehicles, especially automobiles, for soundproofing, heat insulation, decoration,
Various resin composite panels are used for shock absorption and the like. Previously, panels were used that were made by impregnating fiber waste with thermosetting resin and curing or shaping it into a predetermined shape, but in order to reduce cost and weight, panels are now made of polyolefin thermoplastic resin such as polyethylene. Attempts have been made to use a composite panel of a molded plate and a foam as an interior material for automobiles.

However, since the polyolefin thermoplastic resin has low polarity, it is difficult to bond the molded plate to other materials. Surface treatments such as primer treatment with chlorinated polyolefin, plasma discharge treatment, or corona discharge treatment have been proposed as means for improving the adhesion of molded plates. However, primer treatment has a problem in terms of cost because it complicates the manufacturing process, and the above-mentioned discharge treatment has a problem in that it is difficult to apply it to panels with uneven surfaces.

Furthermore, as a method of bonding using an adhesive, an adhesive containing a solvent-based adhesive containing isobrene as a main ingredient and a curing agent such as polyisocyanate is applied to both sides of the adherend and then bonded after drying. Alternatively, a method has been proposed in which a film-like hot-melt adhesive is heated and melted together with an adherend.

However, since solvent-based adhesives require double-sided coating, they are disadvantageous in terms of manufacturing costs, and hot-melt adhesives heat and melt together with the adherend, resulting in problems such as deformation of the adherend.

As an adhesive having relatively good adhesion to molded plates made of polyolefin thermoplastic resin, JP-A-64
Publication No. 31885 discloses a block polyurethane polyol obtained by reaction with a hydrogenated polybutadiene glycol, a polyisocyanate, and a polyol;
Polyurethane adhesives are disclosed that consist of polyisocyanate compounds as crosslinking agents. However, such adhesives have the disadvantage that when attempting to apply the adhesive to an adherend by spray coating, stringiness occurs and it is not possible to apply the adhesive uniformly, and furthermore, the adhesive strength to the rod-shaped object is not sufficient.

(Problems to be Solved by the Invention) The present invention solves the above problems, and its purpose is to provide excellent adhesion to low polarity adherends such as polyolefin thermoplastic resins, and An object of the present invention is to provide an adhesive that can be applied uniformly by spray application. Still another object of the present invention is to provide a method for manufacturing a composite panel in which molded plates of polyolefin thermoplastic resin are bonded using such an adhesive.

(Means for Solving the Problems) The adhesive of the present invention is an active isocyanate obtained by reacting a main component mainly composed of a thermoplastic polyester urethane resin with a hydrogenated hydroxyl-terminated polybutadiene glycol and a polyisocyanate. A two-component mixed adhesive comprising a urethane prepolymer having a urethane prepolymer group, a curing agent containing a polyisocyanate, and thereby achieving the above object.

The method for manufacturing a composite panel of the present invention includes a step of applying the adhesive according to claim 1 to the surface of a molded plate formed of a polyolefin thermoplastic resin and drying the adhesive; a laminated foam, and the foam is placed so as to overlap the dry film of the adhesive and bonded under pressure. pyrene foam, thereby achieving the above objective.

The thermoplastic polyester urethane resin used as the main ingredient of the adhesive of the present invention is an elastomer having urethane bonds in its molecular chain. Usually, an active hydroxyl group of a saturated polyester resin obtained by a condensation reaction of a polybasic acid having two or more carboxyl groups and a dihydric alcohol,
It is a resin consisting of a linear polymer obtained by reacting approximately equivalent amounts of isocyanate groups of a diisocyanate compound.

As the polybasic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, phthalic acid, succinic acid, etc. are used. Examples of dihydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,
4-butanediol, 1,6-hexanediol, neobentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, etc. are used. As the diisocyanate compound, tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, cyclohexylmethane diisocyanate, etc. are used.

The hydrogenated hydroxyl-terminated polybutadiene glycol (hydrogenated polybutadiene glycol) used in the curing agent of the adhesive of the present invention is obtained by hydrogenating polybutadiene glycol in which both ends of the polymer have hydroxyl groups. The skeleton of polybutadiene is a single structure consisting of 1.2 bonds or 1.4 trans bonds; 1,2 bonds and l
, 4 trans bonds; 1.2 bonds, 1.
It has a structure in which 4 trans bonds and 1.4 cis bonds are mixed; or a structure in which 1.4 trans bonds and 1,4 cis bonds are mixed, and there is no limit to the ratio of each bond in the mixed structure. The polybutadiene glycol is hydrogenated in a suitable organic solvent in the presence of a metal catalyst at normal pressure to high pressure. As a metal catalyst, palladium/carbon catalyst,
Known catalysts such as platinum catalysts are used.

Examples of the polyisocyanate used in the curing agent of the adhesive of the present invention include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and triphenylmethane triisocyanate; hexamethylene diisocyanate; 2. 2. Aliphatic polyisocyanates such as 4-trimethylhexamethylene diisocyanate; alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, and hydrogenated tolylene diisocyanate.

These polyisocyanates may be used alone or in combination of two or more.

The adhesive of the present invention contains a main component mainly composed of the thermoplastic polyester urethane resin; a urethane polymer having active isocyanate groups obtained by reacting hydrogenated polybutadiene glycol with polyisocyanate; and polyisocyanate. The curing agent and the thermoplastic polyester urethane resin as the base resin can be prepared, for example, as follows. The thermoplastic polyester urethane resin is dissolved in a suitable solvent to be used as a main ingredient. As a solvent, ethyl acetate, methyl ethyl ketone, acetone, toluene, xylene, 1.
1-trichloroethane and the like are used, and these solvents may be used alone or in combination.

On the other hand, the hydrogenated polybutadiene glycol mentioned above? A urethane prepolymer having active isocyanate groups is prepared by reacting with an excess amount of polyisocyanate. The obtained urethane brevolomer is used as a curing agent together with polyisocyanate without reacting the polyol for the above-mentioned reason. The polyisocyanate is preferably used in an amount such that the isocyanate group is 2.0 to 2.5 equivalents to the hydroxyl group of the hydrogenated polybutadiene glycol. Usually, this urethane brevolomer is mixed with additional polyisocyanate to form a curing agent. The amount of urethane brevolomer used is 0.00 parts by weight per 100 parts by weight of the thermoplastic/plastic polyester urethane resin.
1 to 50 parts by weight is preferable, more preferably 0.5 to 50 parts by weight.
It is 20 parts by weight. If the amount of the urethane prepolymer is less than 0.1 parts by weight, adhesion to the molded plate made of polyolefin thermoplastic resin cannot be obtained, and if it exceeds 50 parts by weight, the initial cohesive force will decrease.

The amount of the additional polyisocyanate used is preferably 2 to 50 parts by weight, more preferably 5 to 3 parts by weight, based on 100 parts by weight of the thermoplastic polyester urethane resin.
It is 0 parts by weight. If the amount of polyisocyanate is less than 2 parts by weight, the adhesive strength upon heating will be low, and if it exceeds 50 parts by weight, the adhesive strength will be reduced.

The adhesive of the present invention is usually a two-component mixed adhesive consisting of the above-mentioned main agent and curing agent, and the two components are mixed immediately before use. In addition to the above-mentioned components, the adhesive of the present invention may contain a solvent, an inorganic filler, a coloring agent, a stabilizer, and other various additives as necessary. The mixed liquid in which the main agent and the curing agent are mixed will not separate into two liquids during the pot life. Since this liquid mixture is a dispersion liquid with a low viscosity, there is no stringiness during spray coating, and the coating can be uniformly applied in the form of fine particles.

The adhesive of the present invention has good adhesion to polyolefin thermoplastic resin molded plates, has excellent initial adhesion, and has adhesion even after the adhesive layer ages under heat or under high temperature and high humidity. will not decrease significantly. Furthermore, the adhesive of the present invention does not need to be applied to both sides of the adherend and can be applied by spraying, so the adhesion operation is easy.
Furthermore, since there is no need to melt the adhesive during bonding, there is no need to deform the adherend.

The molded plate whose main component is a polyolefin thermoplastic resin used in the composite panel manufactured by the method of the present invention means a polyolefin thermoplastic resin such as polyethylene or polypropylene alone, or a polyolefin thermoplastic resin such as polyethylene or polypropylene, or a combination of these resins and glass fibers. It is a molded plate impregnated with an inorganic filler, bulp powder, fiber waste, etc. and shaped into a predetermined shape.

The foam used in the composite panel is a foam made of urethane, polyethylene, or polypropylene. The surface of the polyethylene foam or polypropylene foam may be subjected to a blimmer treatment or a plasma or corona discharge treatment, if necessary.

As the decorative sheet laminated on the foam, knit, cloth, or a thermoplastic sheet such as surface-treated vinyl chloride sheet is used. This foam and a decorative sheet are bonded and laminated using any adhesive and used in the method of the present invention.

According to the method of the invention, a composite panel is manufactured as follows. First, an adhesive containing a mixture of the main ingredient and a curing agent is applied to the surface of a molded plate made of the polyolefin thermoplastic resin and dried. The amount of adhesive applied is 1
00 to 300 g/m' is preferable. Any method can be used to apply the adhesive, but since the adhesive of the present invention can be applied uniformly by spraying, it is convenient to apply it by spraying. The applied adhesive is usually dried at a temperature of room temperature to 120°C.

Next, the molded plate coated with the adhesive and the foam layered with the decorative sheet are arranged so that the dry film of the adhesive and the foam overlap, and are bonded under pressure using a press. Pressure is 0
．． 05-1. 0 kg/cn! , preferably 0.
1~0. Carry out for 1-30 seconds at a pressure of 5 kg/cnf.

It is also possible to improve adhesion by preheating the foam prior to pressing.

For example, heat at 50 to 150 t for 5 to 15 seconds.

The composite panel thus obtained has a molded plate made of polyolefin thermoplastic resin that is well adhered to the foam, and is suitable for use as an interior wall material for automobiles. According to the method of the present invention, it is possible to manufacture composite panels easily and at low cost.

(Example) The invention will now be described with reference to examples.

Examples 1 to 5 Hydroxyl group-terminated polybutadiene glycol (manufactured by Idemitsu Petrochemical Co., Ltd., poly bd R-45HT, 1.4 bonds 80
%, 1.2 bonds 20%, molecular weight 2800) was dissolved in 900 parts by weight of toluene, 10 parts by weight of palladium/hydrogen catalyst was added thereto, and 1.2 parts by weight was dissolved in a hydrogen stream.
Hydrogenation was carried out by stirring for hours. The catalyst and toluene were removed to obtain a waxy hydrogenated polybutadiene glycol (Trial 1=IA). Next, in the parts by weight shown in Table 1,
Sample 8 and diphenylmethane diisocyanate (MDI) were added to toluene and reacted at BO°C for 5 hours to obtain a urethane bleb polymer having active incyanate groups. NCO/OH shown in Table 1 is the ratio of the NGO groups of the isocyanate in the urethane brebolymer to the [10 groups of the hydrogenated polybutadiene glycol. Crude MDI was added to this urethane prepolymer in the weight parts shown in Table 1.
(Sumidur 44V-10, manufactured by Sumitomo Bayer) was added as a curing agent.

Next, put the thermoplastic polyester urethane resin (
Manufactured by Dainippon Ink Co., Ltd., Pandex T5210, adipate polyester/aromatic polyisocyanate type) 100
Parts by weight were dissolved in 700 parts by weight of methyl ethyl ketone to form a main ingredient.

Mix these main ingredients and a curing agent, and apply this adhesive to a glass fiber reinforced polyethylene molded plate (manufactured by Sekisui Chemical Co., Ltd., fiber length 50a + rn, lM fiber diameter 10 microns, 400 g
/ m' glass fiber mat, MI=7, 400g
/m' of high-density polyethylene (molded plate) impregnated with 2
The adhesive was applied by air spray in an amount of 00 g/m', and the adhesive-coated surface was dried at 90° C. for 3 minutes. This molded plate was laminated with knitted urethane foam that had been heated in advance at 100°C for 10 seconds to improve formability, and compressed in a cooling press for 20 seconds at a pressure of 0.2 kg/cnf to obtain a composite panel. .

The resulting composite panels were tested as follows to evaluate the adhesive. After releasing the pressure, move the composite panel 100X
A test piece was cut into a size of 25 mm. Hold this test piece vertically, fix the upper end of the glass fiber reinforced polyethylene molded plate, and attach it to the upper end of the knitted urethane foam.
A weight of 0.00 g was attached, and the peeling length (initial creep property) after 24 hours was measured in an atmosphere at 20°C.

After storing the separately prepared composite panel at 20°C for 3 days,
Cut it into a size of 100 x 25 mm to make a test piece,
The test piece was fixed in the same manner as above, a 100 g weight was attached, and the peel length (thermal creep property) was measured after 24 hours in a heated atmosphere at 90°C.

Composite panels stored at 20°C for 3 days were treated with loOX25[1
A test piece was cut into a size of 1111, and normal peel strength was measured using an autograph in an atmosphere at 20°C. At the same time, the state of destruction of the urethane foam was observed.

In order to compare the adhesive strength in detail, two polyethylene films (IOOX 25 x 0.1 mm) were used, and the above adhesive was applied to one side of each film in an amount of 200 g/m', and after drying at 90 ° C. for 3 minutes, 1kg/c with coated surfaces stacked on top of each other
A composite film was obtained by compression at a pressure of ++f for 20 seconds.

This film was stored at 20° C. for 3 days, and the normal peel strength was measured in the same manner as above. These results are shown in Table 2 together with the results of Examples 6 to 13 and Comparative Examples 1 to 5, which will be described later.

Table 2 also shows the spray conditions when the adhesives of each Example and Comparative Example were sprayed with an air spray gun.

Example 6 Polytail H as hydrogenated polybutadiene glycol
The same procedure as in Example 3 was carried out except for using the same method as in Example 3 (manufactured by Mitsubishi Kaoru Co., Ltd.). The evaluation results are shown in Table 2.

Example 7 Nisso PB as hydrogenated polybutadiene glycol
-Gl-3000 (manufactured by Nippon Soda Co., Ltd., 1.2 bond 90
%, 1.4 bonds 10%, molecular weight 3000), MD
The same procedure as in Example 3 was carried out except that the amount of I was changed to the amount shown in Table 1.

Detailed results are shown in Table 2.

Example 8 Bolitail H as hydrogenated polybutadiene glycol
The procedure was the same as in Example 3 except that Crude M old was used in the amount shown in Table 1 instead of MDI. The evaluation results are shown in Table 2.

Examples 9 to 13 The same as Examples 1 to 5 except that Pandex T5265 (manufactured by Dainippon Ink Co., Ltd., adipate polyester/aliphatic polyisocyanate system) was used as the thermoplastic polyester urethane resin. The evaluation results are shown in Table 2.

Comparative Example 1 This was the same as Example 1 except that the active isocyanate group-containing urethane prepolymer was not used as a curing agent and only crude MDI was used. The evaluation is shown in Table 2.

Comparative Example 2 This was the same as Example 9 except that only crude MDI was used as the curing agent without using the urethane prebomer. The evaluation results are shown in Table 2.

Comparative Example 3 The same as Example 3 except that non-hydrogenated polybutadiene glycol (manufactured by Idemitsu Petrochemical Co., Ltd., poly bd R-458T) was used instead of hydrogenated polybutadiene glycol. The evaluation results are shown in Table 2.

Comparative Example 4 In 45 parts by weight of toluene, 5 parts by weight of Sample A prepared in Examples 1 to 5 was dissolved and mixed with Bandex T-5210 and methyl ethyl ketone in the parts by weight shown in Table 1 to form a main ingredient. The rest was the same as Comparative Example 1. However, the compatibility between the base resin and the curing agent was poor, and phase separation occurred during storage. Therefore, it was not possible to evaluate the adhesive.

Comparative Example 5 In 100 parts by weight of toluene, 00 parts by weight of sample AI prepared in Examples 1 to 5 and 25 parts by weight of MDI (NC'[I
/OH=2.4) and reacted at 80° C. for 5 hours to obtain a urethane prepolymer containing active isocyanate groups. Next, 150 parts by weight of polyester polyol (manufactured by Asahi Denka Co., Ltd., Adeka New Ace F7-68) was charged into another 150 parts by weight of toluene, mixed with the above urethane prepolymer, and reacted at 80°C for 5 hours. A block polyurethane polyol solution (sample B) was obtained. The procedure was the same as in Comparative Example 1 except that 830 parts by weight of this sample was mixed with Vandex T-5210 and methyl ethyl ketone in the parts by weight shown in Table 1 to serve as the main ingredient. The evaluation results are shown in Table 2.

(The following is a blank space) (Effects of the invention) The adhesive of the present invention has excellent adhesion to polyolefin-based thermoplastic resin molded plates, particularly in initial adhesion, adhesion at heat, and adhesion under high temperature and high humidity. Excellent adhesive strength after the agent layer ages. Furthermore, since the main agent and the curing agent are mixed in a dispersed state, this adhesive can be sprayed in good condition and has excellent workability.

Furthermore, according to the method for manufacturing a composite panel of the present invention using an adhesive having the above-mentioned excellent properties, a composite panel with excellent adhesive strength between a polyolefin thermoplastic resin molded plate and a foam can be easily produced at a low cost. It is possible to manufacture with

Such composite panels are suitably used as interior wall materials for vehicles such as automobiles.

that's all

Claims (1)

[Scope of Claims] 1. A urethane prepolymer having an active isocyanate group obtained by reacting a main resin containing a thermoplastic polyester urethane resin with a hydrogenated hydroxyl-terminated polybutadiene glycol and a polyisocyanate, and a polyisocyanate. and a curing agent containing; and an adhesive. 2. Applying the adhesive according to claim 1 to the surface of a molded plate made of a polyolefin thermoplastic resin and drying it; and combining the molded plate and a foam with a decorative sheet laminated thereon. , a step of placing a foam overlappingly on the dry film of the adhesive and adhering it under pressure; the foam is urethane foam, polyethylene foam or polypropylene foam, a method for producing a composite panel.