KR20050087322A - A synthetic sleeper containing woodflour - Google Patents

Abstract

The present invention relates to a synthetic sleeper containing wood powder prepared in consideration of durability and economy, and more specifically, 20 to 35% by weight of glass fiber and at least one synthetic resin selected from PP, PE, PVC, PET or a mixture thereof. Skin layer consisting of ~ 80% by weight and core layer consisting of 30 to 55% by weight of at least one synthetic resin selected from PP, PE, PVC, PET or a mixture thereof, 30 to 55% by weight wood powder and 15 to 20% by weight of other additives It is about a synthetic sleeper containing wood powder bonded by a synthetic resin commonly added to the core layer and skin layer without using this separate adhesive.

Description

A synthetic sleeper containing woodflour

The present invention relates to a synthetic sleeper containing wood powder prepared in consideration of durability and economy, and more specifically, 20 to 35% by weight of glass fiber and at least one synthetic resin selected from PP, PE, PVC, PET or a mixture thereof. Core layer consisting of 30 to 55% by weight of at least one synthetic resin, 30 to 55% by weight of wood powder and 15 to 20% by weight of other additives selected from PP, PE, PVC, PET or a mixture thereof consisting of ~ 80% by weight The present invention relates to a synthetic sleeper containing wood powder bonded by a synthetic resin which is commonly added to a core layer and a skin layer without using an adhesive.

Railway sleepers have mainly used wood and concrete, but wood sleepers are weak in moisture and have a short life due to decay or damage, and are difficult to repair and have problems in supply and demand of wood. Concrete sleepers are made of reinforcing bars with high strength, good durability, and convenience of production, but they are difficult to transport, have problems such as breakage, cracking and noise when they are used.

Therefore, in recent years, development of sleepers to replace them has been variously progressed, and research on synthetic sleepers using synthetic resins or foamed resins has been conducted. Such a synthetic resin sleeper has a high shrinkage and expansion rate, and there is a safety problem in that the accessory material is separated due to a change in shape. In the case of the foamed sleeper, the production cost is very high and there are problems such as environmental pollution.

As a prior art for such a sleeper, Japanese Patent No. 3444724 is formed of a base material layer using a hard urethane and glass fiber, which is a foamed resin, and an abrasion resistant material layer using an elastic urethane and glass fiber, and is used in a traffic or crossing crossing of a vehicle. It describes about the sleeper for tracks laid. However, the present invention has a problem in terms of economy because of the high cost by using a foamed resin.

In addition, Korean Patent No. 187903 describes a recyclable and soft train rail sleeper manufactured by mixing and extruding and injecting polyethylene, coal ash and rice hull powder, but the chaff powder used in the present invention is weak in fiber and made of synthetic resin. Its function is reduced to supplement the strength, the added coal ash serves to control the humidity, but it is easy to cause cracks by lowering the strength, which causes problems in practical use.

In addition, Korean Patent Laid-Open Publication No. 1997-58869 describes a synthetic sleeper manufactured by mixing waste paper and sand with waste synthetic resin such as low density polyethylene, high density polyethylene, polypropylene or polyamide. However, the present invention also has a high shrinkage, expansion and expansion under high temperature of more than 60 ℃ of the lower rail in the summer, it is difficult to maintain the dimensional stability and is not suitable for wear resistance.

Therefore, in order to solve this problem, the present invention aims to provide an economical, environmentally friendly synthetic sleeper with low production cost.

In addition, an object of the present invention is to replace a wooden sleeper, to provide a lightweight, durable and high strength, low-elongation synthetic sleeper with temperature changes. In particular, it is intended to be applied to bridges that are difficult to lay as concrete sleepers or sections of turnouts requiring dimensional stability.

Therefore, the present inventors manufactured a synthetic sleeper containing wood flour having a durability of 5 times or more compared to existing wood sleepers in consideration of light weight of wood flour, durability of high strength synthetic resin and glass fiber, and the like.

The present invention is a core layer consisting of 30 to 55% by weight of wood powder having a moisture content of less than 3%, 30 to 55% by weight of at least one synthetic resin selected from PP, PE, PVC, PET or a mixture thereof and 15 to 20% by weight of other additives; ; 20-35% by weight of glass fibers and 75-80% by weight of one or more synthetic resins selected from PP, PE, PVC, PET, or a mixture thereof. The skin layer is formed above and below the core layer. It relates to a synthetic sleeper containing wood powder, characterized in that it is produced integrally during layer forming.

The wood flour is water vapor generated during extrusion to produce bubbles during cooling, so that the moisture content is within 3%, and 30-150 mesh is used. In order to control the humidity, a small amount of stone powder is added, but when the amount is large, the strength decreases and the impact resistance is markedly lowered.

The other additives use additives known in the field of other synthetic resins such as sunscreens, flame retardants and the like.

In addition, the present invention is characterized in that the skin layer is coated with at least one synthetic resin selected from PP, PE, PVC, PET or a mixture thereof pulverized to a length of 10 ~ 20mm, and then impregnated, prepared by mixing.

Since the skin layer is not uniformly mixed when impregnated with glass fiber and synthetic resin during extrusion processing, the resin layer must be impregnated with resin after the glass fiber is coated with resin in advance to increase the stability and physical properties of the product.

The sleeper of the present invention is divided into three layers in the form of a sandwich, but in the present invention, since the synthetic resin commonly used between layers without using an adhesive serves as an adhesive, the raw material is injected and extruded into three layers in a molding die. It is prepared by molding.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these Examples are only illustrative description of the present invention and the scope of the present invention is not limited to these Examples.

Example 1

First, to impregnate the glass fiber PP resin pulverized to 12 mm size, PP coating 25 weight% of the pulverized glass fiber in order to uniformly mix the two components and then impregnated the coated glass fiber in 75% by weight PP resin, Compounding to prepare a skin layer composition.

 Finely pulverize the wood powder, preferably in a state of water content of less than 3% in a state made of about 30 to 150 mesh. Thus, the core layer composition is prepared by combining 35% by weight of dried wood powder with 50% by weight of PP resin and 15% by weight of various additives, preferably sunscreen and nonflammable, which are added to improve physical properties of products in the field of synthetic resins. It was.

Then, the skin layer composition was added to the injector in the upper and lower portions of the core layer composition, extruded, and cooled by air to prepare a synthetic sleeper.

Comparative Example 1

30 ~ 150 mesh, 35% by weight of wood powder, 50% by weight of PP, and 15% by weight of other additives, preferably sunscreen and flame retardant, blended into a presser, extruded and air-cooled to prepare a synthetic sleeper .

Experimental Example 1: Measurement of Properties

The physical properties of the sleepers prepared in Example 1 and Comparative Example 1 were measured and shown in Table 1. In the case of Comparative Example 1 it can be seen that the strength is reduced by half compared to the sleeper of Example 1. In addition, the stretch ratio also differs by more than five times, and Comparative Example 1 could not be measured at 90 ° C. Therefore, it was confirmed that the glass fibers significantly reduced shrinkage and expansion.

Test Items unit Test Methods Example 1 Comparative Example 1 Flexural strength N / mm2 ASTM D 790 49.3 25.1 Flexural modulus N / mm2 ASTM D 790 2860 1420 Heating elongation rate (length) % 2 hours after 50 ± 2 ℃ 0.02 0.5 Heating elongation rate (width) % 2 hours after 50 ± 2 ℃ 0.1 0.5 Heating elongation rate (length) % 2 hours after 90 ± 2 ℃ 0.05 - Heating elongation rate (width) % 2 hours after 90 ± 2 ℃ 0.1 -

As described above, the sleepers of the present invention have very low elasticity, high dimensional stability, easy installation, light weight, and excellent durability, requiring accuracy of dimensions such as railroad splitters and bridges, or restricting the weight of the sleepers. It can be placed in the receiving place, replacing wood sleepers.

In addition, the sleeper of the present invention can provide an environmentally friendly and low production cost sleeper using wood powder and glass fiber.

Figure 1 shows a cross-sectional view of the synthetic sleepers of the present invention.

1: core layer 2: skin layer

Claims (2)

A core layer composed of 30 to 55% by weight of wood powder having a moisture content of less than 3%, 30 to 55% by weight of at least one synthetic resin selected from PP, PE, PVC, PET or a mixture thereof, and 15 to 20% by weight of other additives; 20-35% by weight of glass fibers and 75-80% by weight of one or more synthetic resins selected from PP, PE, PVC, PET, or a mixture thereof. The skin layer is formed above and below the core layer. Synthetic sleepers containing wood powder, characterized in that they are produced integrally during layer forming. The method of claim 1, wherein the skin layer is coated with at least one synthetic resin selected from PP, PE, PVC, PET or a mixture thereof pulverized to a length of 10 ~ 20mm, impregnated, prepared by mixing Synthetic sleepers containing.