JPH0353110B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a laminated product of polyolefin resin foam having excellent moldability. (Prior art) Polyolefin resin foams have traditionally been used for a variety of purposes as products in various forms through vacuum molding, compression molding, etc. However, these foams have not been commercialized as individual foams. There are few things that happen,
It was usually used in the form of a laminated product that was bonded to a base material such as a plastic sheet or fabric made of polyvinyl chloride or polyolefin using heat fusion or adhesive. The moldability of such laminated products differs significantly depending on the properties of the base material to be laminated to the foam, even if the foam itself has good moldability. No matter how much the moldability of the foam is improved, the moldability will differ depending on the type of base material, so the laminated foam layers will be destroyed during the molding process, resulting in a product with good quality. I had a problem that I couldn't do it. (Problems to be Solved by the Invention) An object of the present invention is to provide a foam layer that is not damaged by the types of skin base materials to be laminated and has good vacuum formability and compression formability. To provide laminated products. (Means for Solving the Problems) The objects of the present invention are as follows: The apparent density is 0.025 to 0.100 g/cc, and the product of breaking strength and breaking elongation at 140°C is at least 30 kg/cc.
cm ² % and has a drawing ratio of at least 0.5 at 130 to 190°C, a skin base whose tensile stress at 50% and 100% elongation is not more than twice that of the polyolefin foam. This can be achieved by a laminated product of polyolefin resin foam made by laminating materials. First, in the present invention, the foam constituting the laminated product has an apparent density in the range of 0.025 to 0.100 g/cc, and the product of breaking strength and breaking elongation at 140°C is 30 kg/cm ² . % or more. Here, the apparent density (g/cc) is a value calculated by accurately cutting the foam into 10 cm squares, measuring the weight and thickness, and using the following formula. Apparent density = weight of foam / 100 x thickness of foam (cm) When the value of this apparent density is smaller than 0.025 g/cc, the stress of the foam is small and the compression recovery and shape retention properties are low. It is not desirable because it is not sufficient and the practical performance as a molded product is not satisfied.
On the other hand, if it exceeds 0.100 g/cc, the compression hardness increases and the cushioning properties (cushion properties) decrease, making it undesirable for molded products such as automobile interior materials. The feature of the present invention is closely related to the characteristics of the skin base material to be laminated to the foam described below, and the product of the breaking strength and breaking elongation of the foam at 140°C is 30 kg/cm. It must be ² % or more. Here, the breaking strength and breaking elongation of the foam at 140℃ and 50% and
The tensile stress at 100% elongation is measured as follows. Using a device attached to a Shimadzu Autograph IS-500 with a heating furnace (manufactured by Daiei Kagaku Seiki Co., Ltd.), the test specimen was heated with dumbbells (No. 1 type) according to the measurement method stipulated in JIS-K-6301. ) shape, JIS
-140 according to the measurement method specified in K-6767
Measurements were made at a tensile speed of 500 mm/min at ℃. The heating time of the test specimen was 5 minutes, and the breaking strength (strength at the breaking point), breaking elongation (elongation at the breaking point), and tensile stress at 50% and 100% elongation were calculated from the recording paper. The unit of breaking strength of foam is stress per unit area (Kg/cm ² ), and the unit of tensile stress at 50% and 100% elongation is stress per width of test piece (Kg/cm 2 ).
cm). If the product of breaking strength and breaking elongation determined by the above measurement method is lower than 30Kg/cm ² %, the foam will not work properly when laminated with a skin base material and molded (vacuum, compression). This is undesirable because the stress and elongation necessary for molding are insufficient, causing problems such as the foam breaking and peeling at the bonding interface, making it impossible to obtain a molded product of practical use. Further, the upper limit of the product of breaking strength and breaking elongation is not particularly limited, but is preferably 600 Kg/cm ² ·%. As a method for producing a polyolefin resin foam having such an apparent density and the product of breaking strength and breaking elongation at 140°C, various known polyolefin resins, such as polyethylene, polypropylene, and ethylene-propylene copolymer, can be used. It can be obtained by a radiation crosslinking foaming method, a chemical crosslinking foaming method, etc. using as a raw material. in particular,
A known thermally decomposable blowing agent such as azodicarbonamide, dinitrosopentamethylenetetramine, etc. and, if necessary, a crosslinking agent that generates radicals upon heating are mixed with the polyolefin resin, and the above blowing agent and crosslinking agent are mixed. It is held at a temperature that does not decompose and is formed, for example, into a sheet shape.
This formed sheet material is subjected to any known method such as ionizing radiation crosslinking method or chemical crosslinking method to obtain a gel fraction of 15 to 60%, preferably 20 to 40%.
%. More specifically, in the case of the ionizing radiation crosslinking method, α, β, γ, X-rays, electron beams, neutron beams, etc. are used as high-energy rays, and a high-energy electron beam irradiation machine is usually used. Crosslinking is achieved by irradiating the sheet with an electron beam at a dose of ~50 Mrad. In this case, 0.1 to 10 parts by weight of various known crosslinking aids, such as divinylbenzene, diallylphthalate,
Electron beam crosslinking may be performed by adding trimethylolpropane triacrylate or the like. Instead of this radiation irradiation, crosslinking can also be carried out by adding an ultraviolet sensitizer such as benzophenone and irradiating ultraviolet rays. In addition, in the case of chemical crosslinking methods, crosslinking methods using organic peroxides such as dicumyl peroxide and ditertiary butyl peroxide, and grafting by kneading vinyl silanes such as vinyltrimethoxysilane with these crosslinking agents. After that, a silane crosslinking method in which crosslinking is performed by a siloxane condensation reaction, etc. can be appropriately applied. The molded product thus obtained is heated in a hot air atmosphere or on a salt bath to rapidly decompose the foaming agent contained within the molded product, thereby converting it into a foam. In addition, to the extent that the object of the present invention is not impaired, the composition used for producing the foam of the present invention may include lubricants, antioxidants, ultraviolet absorbers, colorants, antistatic agents, flame retardants, and others. Various additives can be blended within the range that can achieve the desired purpose. Furthermore, the polyolefin resin foam used in the present invention can be given adhesive properties to at least one side by corona discharge treatment, coating, etc., and can be laminated to improve its workability. or sheets, other foam sheets or metal foils, or extrusion lamination to create a composite structure.
That is, various processing techniques can be applied. A polyolefin resin foam with such an apparent density and a product of breaking strength and breaking elongation at 140°C of 30 kg/cm ² % or more is important for its vacuum forming drawing ratio, especially in vacuum at 130 to 190°C. Forming drawing ratio is 0.5
It is preferable that the vacuum forming drawing ratio is 0.5 or more, so that extremely excellent vacuum formability can be imparted to the laminated product. Next, the skin base material to be laminated on such polyolefin resin foam includes polyvinyl chloride sheet, polyolefin sheet, polyurethane sheet, fiber fabric, etc.
It is necessary that the tensile stress at 50% and 100% elongation is 2.0 times or less, preferably 1.5 times or less, than that of the polyolefin foam. In other words, the tensile stress of the skin base material at 50% and 100% elongation is the
If it becomes larger than 2.0 times, the stress difference between the foam and the skin base material during the molding process may cause the foam to break or peel off at the bonded surface (interfacial peeling), resulting in the desired molded product being damaged. It is undesirable because it makes it impossible to obtain. Methods for laminating the skin base material onto the foam include a method of bonding the two using an adhesive, a lamination method using an extruder, a bonding method using a flame method, etc., but there are no particular limitations. It's not something you can do. (Effects of the Invention) The thus obtained laminated product of the present invention has excellent vacuum formability and compression moldability, and moreover, the laminated foamed product has excellent vacuum formability and compression formability. The body layer does not peel off or break from the epidermis base material, and has excellent quality and form. Therefore, it has excellent moldability in many uses, and almost no trouble occurs during composite molding, for example, as an interior material for automobiles (doors, instrument panels, etc.). (Example) Hereinafter, the effects of the present invention will be explained in more detail with reference to Examples. Examples 1 to 3, Comparative Examples 1 to 2 Polypropylene resin 70 with a melt index (MI) of 1.5 made by random copolymerization of 4% ethylene
Polyethylene resin with MI of 2.0 and density of 0.930 in %30
%, plus azodicarbonamide as blowing agent,
Divinylbenzene as a crosslinking aid and "ionol" as a stabilizer were mixed uniformly, and then a sheet was formed using an extruder. After irradiating the obtained sheet with an electron beam, it was foamed on a heated salt bath to create five types of foams having the characteristic values shown in Table 1. A polyvinyl chloride sheet was laminated on these foams as a skin base material and bonded using an adhesive to obtain a laminated sheet. This laminated sheet has a diameter of 50mmφ and a depth of 25mm.
(L/D=0.5) vacuum forming using a mold to break the bottom (breakage of the foam).

[Table] The state of fracture and interfacial peeling of the bonded surfaces was investigated and compared. These results are also shown in Table 1. From the table, it can be seen that a laminated product that satisfies the conditions stipulated in the present invention has good vacuum formability and compression moldability, and that the laminated foam does not break during molding or that the foam and the skin base It can be seen that it has extremely excellent mechanical performance, with no peeling from the bonded surface.

Claims (1)

[Claims] 1. The apparent density is 0.025 to 0.100 g/cc, and the product of breaking strength and breaking elongation at 140°C is at least 30.
Kg/cm ² % and a drawing ratio of at least 0.5 at 130 to 190°C, the tensile stress at 50% and 100% elongation is not more than twice that of the polyolefin foam. A laminated product of polyolefin resin foam made by laminating skin base materials. 2 In claim 1, the skin base material is a polyvinyl chloride sheet, a polyolefin sheet,
A laminated product made of polyolefin resin foam, the base material of which is selected from the group consisting of polyurethane sheets and textile fabrics.