JPH0732392A - Method for molding lightweight tray mainly comprising fiber reinforced plastic - Google Patents

Abstract

PURPOSE:To reduce the weight of a tray of fiber reinforced plastic and particularly improve marketability and portability of a table service tray for business use by superposing, for molding, a cloth mesh on the upper and lower sides of a molding material comprising a mixture of glass fiber chopped strand, unsaturated polyester, and glass fine hollow bodies. CONSTITUTION:Unsaturated polyester liquid is prepared and chopped strands of glass fibers are added to the liquid, which are mixed, and further glass baloons are added thereto, which are uniformly mixed together. The mixture is used as a principal material for molding, preferably in the form of sheet- shaped SMC. Cloth mesh materials, preferably woven fabrics of glass fiber, non-woven fabrics, or other facing materials, are superposed on the lower and upper sides of the principal material for molding. And the material is molded into a tray-shape by heating and compessing it by means of a compression molding machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel molding method for a lightweight tray, which is mainly made of thermosetting reinforced plastic (FRP), for commercial use.

[0002]

2. Description of the Related Art Reinforced plastic (FRP) made of glass fiber reinforced plastic material contains unsaturated polyester resin composed of a polymer having a network structure as a component and has high strength and impact resistance characteristics. It is known to be used as a tableware tray along with daily sundries. Among these, for trays for dishes and the like which are particularly used for business purposes, a lightweight tray having a large strength and a low specific gravity is desired for stacking a large number of trays or carrying and carrying the dishes or the like. Therefore, the unsaturated polyester is made into a bulk BMC or a sheet SMC in which a filler such as glass fiber or calcium carbonate is mixed, and these are processed as a tray by injection molding or compression molding.

[0003]

The tray, which is a molded product of these reinforced plastic materials, has a limit of a specific gravity of 1.7 to 1.9, and it is a particular task to make the tray even lighter to make a molded product having a small specific gravity. It has been desired as a means to improve the productability of portable trays and the workability of carrying them. Further, the tray using a reinforced plastic material as a molding material has many advantages, but on the other hand, it is easy to be charged, so that there is a problem in that dust and dirt are easily attached to the surface. Further, since the weather resistance is somewhat difficult and the strength and hardness are large and hard, it is necessary to improve the difficulty of causing stress cracking (cracking), cracking, cracking and the like due to long-term use in cold regions.

[0004]

To achieve the above object, the present invention mainly comprises a sheet-shaped molding material obtained by mixing a glass micro hollow body (glass balloon) with a reinforced plastic material,
A method for forming a lightweight tray mainly made of reinforced plastic (FRP), which is characterized in that sheet-like cross mesh materials made of glass or other material are laminated on the upper and lower surfaces and heated and pressed in a tray shape to form the tray. provide.

[0005]

[Function] The reinforced plastic material, which is the main material component of the tray, reduces the ratio of components used of unsaturated polyester and calcium carbonate by adding a hollow glass balloon containing air, and the overall specific gravity becomes smaller and the weight is reduced. To do. Further, since the surface cross-mesh material exists in the surface layers of the upper and lower surfaces of the unsaturated polyester material, it has a function of buffering an external impact, and the charging effect of the tray surface is reduced, so that the adhesion effect of dust is reduced.

[0006]

EXAMPLES Examples of the present invention will be described. An unsaturated polyester liquid for molding is prepared and chopped strands of known glass fiber are added thereto in a predetermined amount (preferably with respect to unsaturated polyester) according to a conventional method. 25-35% by weight)
Further, a glass balloon having a particle size of preferably 10 to 150 μn and a specific gravity of 1.0 or less is uniformly mixed with the unsaturated polyester in an amount of preferably 10 to 30% by weight. SMC. At the time of molding by a molding machine, a glass mesh woven cloth, nonwoven cloth or other surface layer material is preferably laminated as a cross mesh material on the lower layer and the upper layer of the molding main material. Then, the molded material having a three-layer structure is heated and compressed by a compression molding machine, preferably by a simultaneous molding method according to a conventional method to obtain an integrated molded material in which the cross mesh material exists in the upper and lower layers. Glass balloons that are mixed with unsaturated polyester, which is the main molding material, have a specific gravity of the molded product that decreases with the mixing ratio, but on the other hand, the strength of the molded product decreases with the increase of the mixing ratio of the glass balloons. It is preferable to use an appropriate mixing ratio.

[0007]

[Effect] The lightweight tray mainly made of the reinforced plastic obtained according to the present invention has a specific gravity of about 1.1, which is different from the conventional one, depending on the amount of the glass balloons mixed, and thus saves work efficiency and efficiency. There are benefits to help. In addition, the presence of the cross mesh in the surface layer increases the impact strength from the outside, and prevents the exposure process to the surface of the glass balloon due to the molding process that occurs when the cross mesh does not exist and the abrasion of the surface during use. As a result, the adhesion of dust to the surface of the tray that would otherwise occur is reduced, which impairs the commerciality and quality of the tray, and its effect is remarkable.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29L 9:00

Claims (1)

[Claims] 1. A molding material comprising an unsaturated polyester resin mixed with glass fiber chopped strands and glass micro hollow bodies as a main material, and a cross mesh laminated on the upper and lower surfaces thereof, and heated and pressed in a tray shape for molding. A method for forming a lightweight tray whose main material is reinforced plastic.