JPH0118858B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention involves the production of molded products with excellent heat resistance that do not peel or blister even when used in a hot atmosphere by coating the surface of urethane foam with a fiber-reinforced thermosetting resin molding material (hereinafter referred to as FRP). Conventionally, composite molded products whose core material is urethane foam and whose surface material is FRP thin metal sheets, etc., are often exposed to high-temperature atmospheres of 50°C or higher, such as ceiling panels and side wall panels of automobiles, etc. It is used for panel-shaped molded products such as hot water storage tanks and hot storages, and cross-sectional panels for construction, but such molded products release gases such as chlorofluoro hydrocarbons and carbon dioxide contained in the urethane foam due to temperature rise. Due to volatilization or expansion of components, peeling and blistering phenomena occur at locations where the adhesive strength layer is weak, such as the interface between the surface material/core material or the interface between the skin layer and core layer in the case of injection foam molded products. This is particularly exacerbated in environments with temperatures above 80°C.As an improvement method, adhesives or primers can be applied to improve the adhesion performance between the surface material and the core material. In the case of polyurethane foam molded products with a skin layer, methods have been proposed to improve adhesion by roughening the surface. However, these methods do not fundamentally solve the problems of peeling and blistering. As a result of intensive research to solve the above problems, the inventors found that when urethane foam alone is heated, especially at temperatures above 80°C, the amount of gas components contained in it volatilizes is extremely large. Although it is preferable, a coating layer of urethane foam is used to overcome the drawback that the deformation of the foam becomes significantly large.
After making a through hole reaching the urethane foam from the surface of the FRP layer and drying it by heating in the range of about 50 to 140 degrees Celsius, I sealed it with a heat resistant material such as resin or putty, and it did not peel off even when used in a hot atmosphere. It was discovered that a molded product without blisters can be obtained, leading to the present invention. That is, the present invention improves the surface of the urethane foam.
After coating the FRP, the FRP is cured, and then a through hole is provided that reaches the urethane foam from the molding material layer, and after drying by heating, the hole is sealed with a heat resistant material. Excellent heat resistance. A method for manufacturing a molded article is provided. The urethane foam used in the present invention may be any known and commonly used hard urethane foam, and usually contains a polyol, a polyisocyanate and a blowing agent such as water or a chlorofluorohydrocarbon, and other additive components such as a catalyst, a crosslinking agent, It is obtained from foam regulators, stabilizers, etc. The urethane foam may be formed by any commonly used forming method. Further, the foam may be either an injection foam with a skin layer or a foam without a skin layer. The shape of the urethane foam can be varied depending on the application, such as a plate shape, an automobile door shape, a ceiling shape, etc. The FRP used in the present invention contains, for example, a thermosetting resin such as an unsaturated polyester resin, a vinyl ester resin, or a phenolic resin. Further, the fiber reinforcing agent used in such a molding material is preferably glass fiber or carbon fiber, and other synthetic fibers or metal fibers may also be used depending on the case.
Incidentally, the molding material may contain any known additives such as curing agents, accelerators, fillers, pigments, mold release agents, and other additives, as required. The method for coating the urethane foam with FRP used in the present invention is to apply FRP onto the surface of the urethane foam by a known molding method such as a hand lay-up method, a spray-up method, a resin injection method, a press method, or a continuous molding method. I can do it.
In addition, in the present invention, the surface of the urethane foam is coated, but when the urethane foam is plate-shaped, the sides other than the top and bottom surfaces are coated with a metal plate such as an iron plate, a steel plate, an aluminum plate, or a resin plate, regardless of its type. It may be covered with something. Although it depends on the shape of the urethane foam, the coverage area of the urethane foam with FRP is usually 77% or more, preferably 87% or more. The method for drilling holes in the sandwich molded product produced as described above may be any commonly used method, such as a hand drill, a repeater,
Set the drill on a drilling machine, etc. and drill the hole. The diameter of such holes is not particularly limited, but the smaller the diameter is, the better, taking into account the opening process using heat-resistant material during sealing and the appearance of the molded product, but in consideration of gas volatilization efficiency, reduction in strength, etc. ~10 mm is preferable. In the present invention, heating and drying is performed to volatilize gas components after hole-opening processing, and the temperature conditions at that time are usually in the range of 40 to 150°C. If the temperature is low, the volatilization efficiency is poor and a long time is required, and if the temperature is high, there is a problem of decomposition of the urethane foam, so the temperature range is preferably 50 to 140°C. Next, the molded product is heat-dried and hole-closed, but it is best to do this as soon as possible after heat-drying; if the hole-closed process is delayed, seal the hole opening with cellophane tape, etc. It's good to keep it. The heat-resistant material sealed in the pore-closing process may be any commonly used material, such as thermosetting resins such as unsaturated polyester resins and epoxy resins, and fillers, curing agents, pigments, etc. as necessary. It is possible to mix and use various additives and the like. As such a material, a room temperature curing type is preferable.
Incidentally, the hole-closing process is carried out by a commonly used method, for example, by hand work, by using a caulking gun, or, if the opening is small, by injecting liquid resin with a syringe or the like. The sandwich molded product obtained in this way does not peel or blister even when used in a hot atmosphere, and can be used for panel-shaped molding of ceiling panels and side wall panels of automobiles, hot water tanks, hot storage cabinets, etc. for,
Useful for cross-sectional architectural panels, etc. Hereinafter, the present invention will be explained in detail by giving Examples and Comparative Examples. Note that parts and percentages in the examples are based on weight. Example 1 HiproxRQ- with a wooden mold of 500 x 500 x 200 (mm)
350 (polyol: manufactured by Dainippon Ink Chemical Co., Ltd.) 100 parts,
Urethane foam bread was manufactured by mixing 144 parts of HiproxSP-299 (crude MDI: manufactured by Dainippon Ink Chemical Co., Ltd.) and 10 parts of Freon-11 (foaming agent: manufactured by Daikin Company), and after being left at room temperature for one week, it was cut with a cutter. thickness 50
Slab foam specimens of 1000 cm ³ mm, width 100 mm, and length 200 mm were cut. The basic physical properties of this foam are a foam density of 0.103 and a compressive yield strength of 10.7 Kg/cm ²
(23°C, parallel to the foaming direction). This foam molded product is made of unsaturated polyester resin (Polylite FH-123: manufactured by Dainippon Ink Chemical Co., Ltd.)
1.2 parts of 55% methyl ethyl ketone peroxide (MEKPO) was impregnated into 450 g/m ² chopped strand glass mat (manufactured by Nittobo Co., Ltd.) so that the glass content was 30%. The sheets were laminated on the top, bottom, and side surfaces using a Handley Up, and after being left at room temperature for 48 hours, one through hole with a diameter of 5 mm was made in the center, and the sheets were heated and dried at 120° C. for 2 hours. Polylite FH− after drying and cooling
123, 50 parts of talc, and 1.5 parts of MEKPO were mixed to form a putty and the opening was sealed with it. The obtained molded product was subjected to a heat resistance test at 90°C for 15 hours. The results were good as shown in Table 1. Comparative Example 1 A molded article (plate) without holes in Example 1 was obtained, and a heat resistance test was conducted on the molded article (plate).
As a result, as shown in Table 1, blistering occurred on the entire surface. Example 2 A molded article was obtained in the same manner as in Example 1, except that the heat drying conditions were changed to a temperature of 80° C. and a drying time of 5 hours. Table 1 shows the results of the heat resistance test of the obtained molded product.
Shown below. Comparative Example 2 A molded product corresponding to the non-perforated molded product in Example 2 was obtained, and a heat resistance test was conducted on the molded product. The results are shown in Table-1. Examples 3 and 4, Comparative Example 3 As shown in Table 1, Example 1 except that the shape of the urethane foam or the heat drying conditions were changed.
A molded product was obtained in the same manner as above. Also, for comparison, a molded product without holes was obtained when obtaining the above molded product. The results of these heat resistance tests are shown in Table-1. Example 5 Urethane foam was produced in the same manner as in Example 1 except that the amount of Frephone-11 added was changed to 22 parts. The basic physical property of this foam is the foam density
The yield strength was 0.05 g/m ³ and the compressive yield strength was 4.1 Kg/cm ² .
Using this foam, a molded product was obtained in the same manner as in Example-1. The test results are shown in Table-2. Comparative Example 4 A molded product corresponding to the non-perforated molded product in Example 5 was obtained, and a heat resistance test was conducted on the molded product. The results are shown in Table-2. Example 6 A molded product was obtained in the same manner as in Example 5 except that the drying time was changed to 5 hours. The results of the heat resistance test are shown in Table-2. Example 7 A molded product was obtained in the same manner as in Example 5 except that the shape of the urethane foam and the diameter of the through hole were changed. The results of the heat resistance test are shown in Table-2. Example 8 A urethane foam with a thickness of 3 cm, a width of 20 cm, and a length of 20 cm was created in the same manner as in Example 1. This foam was placed in a compression mold, and the top, bottom, and side walls were coated. 450 impregnated with the same unsaturated polyester resin compound used in Example-1.
Two continuous glass mats (manufactured by Asahi Fiber Co., Ltd.) each having a weight of 10 kg/m ² (glass content: 30%) were arranged and compression molded at a pressure of 10 kg/cm ² , a temperature of 50° C., and a time of 10 minutes. The resin compound at this time was 100 parts of Polylite PM-141 (unsaturated polyester resin: manufactured by Dainippon Ink Chemical Co., Ltd.), weight calcium carbonate.
50 parts, 1.0 part of 55% MEKPO and 0.6 part of 6% cobalt naphthenate was used. Thereafter, molded products were obtained in the same manner as in Example-1. The results are shown in Table-2. Comparative Example 3 A molded article corresponding to the molded article without openings in Example 3 was obtained, and a heat resistance test was conducted on the molded article. The results are shown in Table-2.

【table】

[Table] (Note) Evaluation of heat resistance test ○: No abnormality △: Partial peeling ×: Fully blistered

【table】

Claims (1)

[Claims] 1 After coating the surface of the urethane foam with a fiber-reinforced thermosetting resin molding material, the molding material is cured, and then through-holes are provided that reach the urethane foam from the molding material layer, and after drying by heating, the holes are A method for producing a molded article with excellent heat resistance, which is characterized by sealing the molded product with a heat-resistant material.