JPH0919935A - Bonding method of resin and plastic product containing different resin having improved bonding strength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin bonding method, by which the bonding strength between a hollow molded article obtained by utilizing a rotational molding and a foamed urethane resin poured in the hollow cavity of the hollow molded article can be enhanced, and a plastic product, which is manufactured by the above-mentioned method and in which the bonding strength between the rotational thermoplastic resin molded article and the foamed urethane resin within the rotational thermoplastic resin molded article is enhanced. SOLUTION: A hollow molded article 2 is produced by means of a rotational molding from a shock thermoplastic resin mixed with 0.029-8.9wt.% of an inorganic filler so as to pour a foaming urethane resin 3 in the hollow cavity of the mold article.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adhering different kinds of resins and a plastic product containing different kinds of resins having improved adhesion strength. More specifically, the present invention relates to the adhesiveness between a thermoplastic resin and a urethane resin in producing a product obtained by injecting a urethane resin into the hollow inside of a thermoplastic resin molded article obtained by utilizing a rotational molding method. And a plastic product having an improved adhesive strength between a molded product obtained by a rotational molding method and a urethane resin filled in the hollow interior of the molded product.

[0002]

2. Description of the Related Art Rotational molding is one of the molding methods that have recently been attracting attention as a method for molding hollow plastic products. In the rotational molding method, the raw material resin is placed in a hollow split mold, the split mold is sealed, and then heated while rotating (rotating or revolving) around two rotating shafts orthogonal to each other. Is melted, the molten resin is evenly attached to the inner wall of the mold, and a hollow molded product is taken out after cooling. This method is superior to other molding methods, for example, the manufacturing cost of the mold is cheaper than the injection molding method, blow molding method, etc., and the delivery time is short. Is advantageous for manufacturing.

As described above, the rotomoulded product has a merit that it is possible to manufacture a large-sized molded product because the raw material resin is uniformly attached to the inner wall of the mold at the time of molding so that the uneven thickness is small. Due to technological improvements, the production volume is increasing and the product field is also expanding. Along with that, the demand for the molded product obtained by the rotational molding method is expected to expand to applications in which it is necessary to inject other resin materials, for example, urethane foam resin into the molded product. . An example of a product manufactured by injecting another resin material inside the rotational molded body is a float or floater used as a float used to prevent the diffusion of oil leaked at port facilities, etc. It is placed in the cooler box (the inner urethane resin acts as a heat insulating material), or as a buffer when the vehicle collides with a branch road on the road. There is a cushion drum used (softening the impact with urethane resin injected inside).

When manufacturing a product in which another resin material is injected into the rotomolded product, it is necessary to sufficiently adhere the injected resin to the rotomolded product. Heretofore, the following methods have been known as general methods for improving the adhesiveness between resin materials. (1) A method of applying an adhesive to a molded product. (2) A method in which an adhesive resin is mixed with a raw material resin to obtain a molded product. (3) A method of corona treating the adhesive surface of the molded product. (4) A method of adhering the adhesive surface of the molded product in a molten state.

However, each of these methods has its own inconvenience, and it cannot be expected to improve the adhesiveness between the rotationally molded product and the injected resin. Specifically, (1) above
In the methods of (3) and (4), when injecting urethane resin into the inside of the rotational molded product, for example, the adhesive is applied to the inner surface of the rotational molded product, the corona treatment of the inner surface and the melting are performed uniformly. I can't do it. In addition, the above method (2) cannot obtain sufficient adhesive strength between the rotomolded product and the injected resin.

[0006]

In a product in which, for example, a urethane foam resin is simply injected into the hollow cavity of a rotomolded product of a commonly used material, the adhesiveness between the rotomolded product and the urethane foam resin is weak, and the product is in use. Moreover, the rotationally molded product and the urethane foam resin inside are easily separated. As a result, this causes swelling or cracking of the product, which causes various problems such as a liquid leakage phenomenon from the pipe mounting portion and a predetermined heat insulating effect not being obtained.

The present invention aims to improve the adhesive strength between a thermoplastic resin molded product obtained by utilizing the rotational molding method and the urethane foam resin injected into the molded product, so that the thermoplastic resin and the urethane foam resin are combined. It is intended to provide a method of firmly adhering. Another object of the present invention is to provide a product manufactured by this method, which has improved adhesive strength between a thermoplastic resin molded product and a urethane foam resin inside thereof.

[0008]

The method of the present invention comprises 0.029
By producing a hollow molded product by a rotational molding method from a raw material thermoplastic resin containing an inorganic filler in an amount of more than 1% by weight and less than 8.6% by weight, and by injecting a urethane foam resin into the hollow cavity of this molded product, It is a resin bonding method characterized by bonding a hollow molded article of a thermoplastic resin and an injected urethane foam resin.

The product of the present invention is also a hollow molded article produced by a rotational molding method from a raw material thermoplastic resin mixed with an inorganic filler in an amount of more than 0.029% by weight and less than 8.6% by weight, and a hollow molded article of this molded article. It is a plastic product characterized by being made of urethane foam resin in a hollow cavity.

[0010]

[Function] The raw material thermoplastic resin exceeds 0.029% by weight and 8.
A plastic product manufactured by injecting a polyurethane foam resin into the hollow cavity of a hollow molded product obtained by the rotational molding method using a composition in which an inorganic filler in an amount of less than 6% by weight is mixed, It was found that the adhesive strength between the inner wall and the urethane foam resin had a surprising strength. Moreover, this improvement in adhesive strength provides a low-cost, high-quality product without impairing the moldability of the hollow molding product by the rotational molding method and without impairing the simplicity of the rotational molding method. Enable you to do.

The inventors have found that it exceeds 0.029% by weight and is 8.6
The inner surface of the hollow cavity (urethane foam resin injection side) of the molded product made by the rotational molding method using the thermoplastic resin composition in which the amount of the inorganic filler is less than wt% is the rotational molding without the inorganic filler. It was confirmed that it was rough compared to the inside of the product. Further, it is presumed that the inorganic filler mixed in the raw material resin is more contained in the inner surface side of the hollow cavity during the rotational molding. It is considered that, for the above-mentioned two reasons, it contributes to the improvement of the adhesive force with the foamed polyurethane resin injected later into the hollow cavity.

The rotomolded article obtained by using a composition in which 8.6% by weight or more of an inorganic filler is mixed with the raw material thermoplastic resin has large deformation and cannot be put to practical use. In addition, when a composition in which 0.029% by weight or less of an inorganic filler is mixed with a thermoplastic resin is used, sufficient adhesive force can be obtained even if polyurethane foam is injected into the hollow cavity of the obtained rotomolded product. I can't get it. A more preferable amount of the inorganic filler mixed in the raw material thermoplastic resin is 0.059 to 6.6% by weight.

The thermoplastic resin used in the present invention may be any resin that is plasticized by applying heat. For example, an olefin resin such as a polyethylene resin or a polypropylene resin can be advantageously used. Further, in the present invention, any thermoplastic resin other than the olefin resin may be used, and examples thereof include polystyrene resin, vinyl chloride resin, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), acrylonitrile. -Styrene copolymer resin (AS resin), polycarbonate resin, nylon resin, etc. can be mentioned. Also,
As the thermoplastic resin, only one kind may be used, or two or more kinds may be used at the same time.

The inorganic filler used in the present invention may be either an inorganic compound filler or a filler based on an inorganic compound. Examples of preferable inorganic fillers include calcium carbonate, diatomaceous earth, clay, talc, mica, zinc oxide, calcium silicate, aluminum silicate, magnesium silicate and the like. These inorganic fillers may have any shape and size as long as they do not adversely affect the adhesiveness between the rotationally molded product and the injected resin. As for the inorganic filler, only one kind may be used, or two or more kinds may be used at the same time.

In the present invention, the polyurethane foam resin to be injected into the rotational molded article is not particularly limited,
It is possible to use an appropriately selected product according to the intended use of the product. Further, in the present invention, antioxidants, pigments, weathering agents and the like which are usually used by being blended with the raw material resin in the step of molding a plastic product may be used as required.

FIG. 1 shows a cool box which is an example of the plastic product of the present invention. This cold insulation box 1 is a surface material 2 of a molded product of a thermoplastic resin produced by a rotational molding method.
And the urethane resin 3 filled in the cavity inside. A suitable inorganic filler (not shown) is mixed in the surface material 2 of the thermoplastic resin according to the present invention to enhance the adhesive strength with the filled urethane resin, so that the surface material is swollen or cracked. It can be used for a long time without.

[0017]

EXAMPLES Next, the present invention will be further described with reference to examples, but the present invention is not limited to the following examples.

Example 1 1700 g of polyethylene resin (R-90 manufactured by Mitsubishi Chemical Corporation)
KP) and 120 g (corresponding to 6.6% by weight) of calcium carbonate (manufactured by Shiraishi Kogyo Co., Ltd., Whiten 307) are mixed, and the mixture is put into a rotary molding square tank mold having an internal volume of 10 liters. It was The mold was placed in a gas oven at 250 ° C. and heated for 20 minutes while rotating at a revolution speed of 1.875 rpm and a rotation speed of 11.25 rpm. Then, the mold was taken out of the gas oven, and while being naturally cooled for 30 minutes while rotating under the same conditions as the rotation in the gas oven, the molded product was taken out from the mold.

The amount of deformation of this molded product was visually inspected to determine the moldability. Next, polyol component (Takeda Pharmaceutical Co., Ltd., Actol RL-72R) and isocyanate component (Takeda Pharmaceutical Co., Ltd., Takenate IS-01T).
Polyurethane raw material 320 mixed with 100 and 113 in a ratio of 100: 113
g was put into the hollow cavity of the above-mentioned rotationally molded product and allowed to foam to obtain a plastic product having a foamed polyurethane resin filled therein.

Three 5 cm square samples were taken from this plastic product, fixed on the sample support base of the autograph with the urethane resin layer of the sample on the lower side, and the polyethylene resin layer was pulled upward to draw the space between the resins. The adhesive strength was measured.
Arithmetic mean of the measured adhesive strength value divided by 25,
The adhesion strength of the sample was recorded.

Subsequently, the sample after the measurement of the adhesive strength was visually inspected, and when the peeling was observed at the interface between the polyethylene resin layer and the urethane resin layer, "interfacial peeling" was performed, and when the urethane resin layer was broken, "urethane" was used. Material destruction "and these numbers were recorded.

[0022] Except that was changed to the amount of calcium carbonate used in Examples 2 and 3 Example 1 4.5 wt% (Example 2) and 2.3 wt% (Example 3), as in Example 1 Met.

Examples 4 to 7 The types of calcium carbonate used in Example 1 were Whiten 3
Change from 07 to Shiragian CCR (manufactured by Shiraishi Kogyo Co., Ltd.) with 40 mesh, and add 0.58 to the polyethylene resin.
Similar to Example 1 except that wt% (Example 4), 0.29 wt% (Example 5), 0.15 wt% (Example 6), and 0.059 wt% (Example 7). .

Example 8 The same as Example 2 except that the calcium carbonate used in Example 2 was replaced with diatomaceous earth, Isolite CP-F (made by Isolite Industry Co., Ltd.).

Example 9 The calcium carbonate of the inorganic filler used in Example 1 was changed from Whiten 307 to Sunlite SL-700 (manufactured by Takehara Chemical Industry Co., Ltd.), and the amount used was 80 g (equivalent to 4.5% by weight). Same as Example 1 except that

Example 10 1400 g of 1700 g of the polyethylene resin used in Example 9
Of polypropylene resin (SC-13 55RM manufactured by NESTE Chemicals (Belgium)), and the type and amount of calcium carbonate from 80 g of Sunlight SL-700 to whiten
307 (manufactured by Shiraishi Kogyo Co., Ltd.) was changed to 66 g (equivalent to 4.5% by weight), 2.8 g of a new pigment (green pigment TE5532 manufactured by Toyo Ink Mfg. Co., Ltd.) was used, and in a gas oven The heating condition is 250 ° C for 20 minutes to 28 minutes.
Same as Example 9 except changed to 12.5 minutes at 0 ° C.

Comparative Example 1 The same experiment as in Example 1 was carried out except that the mixing amount of calcium carbonate in Example 1 was changed to 8.6% by weight. However, in Comparative Example 1, the deformation of the rotomolded product was large (poor moldability) and the urethane resin could not be injected, so the measurement of the adhesive strength and the subsequent visual inspection of the sample were not performed.

Comparative Example 2 The same experiment as in Example 4 was carried out except that the amount of calcium carbonate mixed in Example 4 was changed to 0.029% by weight.

Comparative Example 3 The same as Example 1 except that calcium carbonate was not added to the raw material polyethylene resin.

Comparative Example 4 The same as Example 10 except that calcium carbonate as an inorganic filler was not added to the raw material polypropylene resin.

The type of resin used in each of the above examples,
Tables 1 and 2 show the types and addition amounts of the inorganic fillers and the obtained results.

[0032]

[Table 1]

[0033]

[Table 2]

As is apparent from these tables, in the case of the present invention (Examples 1 to 10), the adhesive strength between the rotationally molded product and the urethane foam resin is remarkably stronger than that in the comparative example. Further, when the broken state of the sample after measuring the adhesive strength is observed, in the present invention, no interfacial peeling between the rotational molded article and the injected polyurethane resin is observed, whereas in the case of the comparative example, interfacial peeling is observed. It was From this, it can be seen that the effect of improving the adhesiveness between the rotationally molded product and the injected resin according to the present invention is very large.

Further, as is clear from the above embodiment,
In the present invention, as the inorganic filler used for improving the adhesive strength between the rotomolded product and the injected resin, those which are naturally produced in large quantities and can be obtained at low cost can be used. Further, also in the manufacturing process, it is not necessary to drastically change the existing process because only the inorganic filler is mixed with the raw material thermoplastic resin. Therefore, according to the present invention,
It is possible to supply a useful product by increasing the adhesive strength between the rotomolded product and the injected urethane foam resin at a low cost.

[0036]

As described above, according to the present invention,
By improving the adhesive strength between the thermoplastic resin molded product obtained by the rotational molding method and the urethane foam resin filled in the hollow cavity, it becomes possible to firmly bond the two and rotate it during use. It is possible to supply a useful product that does not cause swelling or cracking due to peeling between the molded product and the urethane foam resin inside.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view illustrating a plastic product of the present invention.

[Explanation of symbols]

 1 ... Plastic product 2 ... Thermoplastic resin surface material 3 ... Foamed polyurethane resin

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B32B 5/18 B32B 5/18 27/32 27/32 C 27/40 27/40 C08L 75/04 NGH C08L 75/04 NGH C09J 5/00 JGL C09J 5/00 JGL 175/00 JEZ 175/00 JEZ // B29K 23:00 75:00 105: 04 105: 16 B29L 9:00 22:00 (72) Invention Person Masaru Fujimoto 2056 Kawamukai, Habikino City, Osaka Prefecture Summit Juice Industry Co., Ltd. (72) Inventor Tsuguo Mitani 2056 Kawamukai, Habino City Osaka Prefecture Summit Juice Industry Co., Ltd.

Claims (8)

[Claims] 1. A hollow molded article is produced by a rotational molding method from a raw material thermoplastic resin containing an inorganic filler in an amount of more than 0.029% by weight and less than 8.6% by weight, and a urethane foam resin is produced in the hollow cavity of the molded article. A method for adhering a resin, characterized in that a hollow molded article of a thermoplastic resin and an injected urethane foam resin are adhered by injecting. 2. The method according to claim 1, wherein the thermoplastic resin is an olefin resin. 3. The thermoplastic resin is polyethylene resin, polypropylene resin, polystyrene resin, vinyl chloride resin, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-styrene copolymer resin, polycarbonate resin, nylon resin, or a mixture thereof. The method according to claim 1, characterized in that 4. The inorganic filler is calcium carbonate,
4. A method according to any one of claims 1 to 3, characterized in that it is diatomaceous earth, clay, talc, mica, zinc oxide, calcium silicate, aluminum silicate, magnesium silicate or mixtures thereof. 5. A hollow molded article produced by a rotational molding method from a raw material thermoplastic resin mixed with an inorganic filler in an amount of more than 0.029% by weight and less than 8.6% by weight, and a urethane foam in the hollow cavity of this molded article. Plastic products characterized by being composed of resin. 6. The product according to claim 5, wherein the thermoplastic resin is an olefin resin. 7. The thermoplastic resin is polyethylene resin, polypropylene resin, polystyrene resin, vinyl chloride resin, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-styrene copolymer resin, polycarbonate resin, nylon resin, or a mixture thereof. The product according to claim 5, characterized in that 8. The inorganic filler is calcium carbonate,
Product according to any one of claims 5 to 7, characterized in that it is diatomaceous earth, clay, talc, mica, zinc oxide, calcium silicate, aluminum silicate, magnesium silicate or mixtures thereof.