JP2542240B2 - Pneumatic molding of pulp fiber sludge - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for molding a molded product having a shell-like structure such as a packing material and a cushion material from a pulp fiber sludge made from waste paper, waste pulp material, etc. as a raw material. .

2. Description of the Related Art Conventionally, a molding method using this kind of pulp fiber sludge as a raw material is generally called a wet suction molding method, and the pulp fiber sludge is placed around a mold having a water-permeable structure such as a wire net to form a pulp fiber. The sludge is sucked into the mold to drain the water, and at the same time, pulp fibers are deposited on the mold to form a symmetrical molded body, and then the hydrous pulp fiber molded body is subjected to pressure dehydration or not. In most cases, molding was performed by natural or forced drying.

Moreover, the pulp fiber molded body molded by the above method is fragile in strength because the molding structure is simply due to the entanglement of the fibers, and therefore the pulp fiber sludge is preliminarily thermosetting or thermoplastic. Synthetic resin is mixed and contained, and after molding by suction molding method, it is heated and pressed to melt and solidify the synthetic resin contained inside the molded body, thereby solidifying and binding the synthetic resin between the complex contact of fibers, and increasing the strength. The method of increasing was adopted.

The flame-retardant treatment has been carried out by mixing a flame-retardant agent with pulp fiber sludge.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The above-mentioned conventional wet suction molding method sucks pulp fiber sludge into a water-passing type to deposit pulp fibers on the water-passing type to form a hollow shape having a desired shape. I was manufacturing the body,
In order to deposit the pulp fibers by sucking them together with water in a water-passing type, when forming the layer of pulp fibers in the hollow body, not so much pressure or cohesive force is applied, and the layer density does not become dense. Furthermore, for suction with water, the pulp fibers are biased to a large part of the discharge speed and discharge force of water,
The layers of the hollow body are likely to be non-uniform, and defects of uneven thickness are particularly prominent at bends and the like.

Furthermore, the conventional synthetic resin mixing method for increasing the strength of the molded body or the flame retardant treatment method for the flame retardant treatment is a powdery, granular or Liquid synthetic resin or flame retardant is mixed, but it is not uniformly dispersed due to the difference in specific gravity with fibers or the difference in specific gravity with water, and it does not impregnate inside the fiber itself, and therefore synthetic resin or flame retardant. The strength of the molded product was not increased or the flame retardancy was not improved in comparison with the amount used.

The method of the present invention is also intended to make full use of the effects by effectively utilizing the addition of synthetic resin or flame retardant.

Means for Solving the Problem The present invention provides the following means for overcoming the drawbacks arising from the above-mentioned conventional techniques.

That is, a closed cylinder was provided so as to cover the upper surface of the water-permeable type that can be drained, and pulp fibers that had been crushed and defibrated and dried, and a required amount of liquid synthetic resin and flame retardant were placed in the closed cylinder. After that, the synthetic resin and the flame retardant are impregnated in the pulp fiber by keeping the inside of the closed cylinder at a reduced pressure atmosphere lower than the atmospheric pressure, and then the pulp fiber is taken out from the inside of the closed cylinder and subjected to preliminary heat treatment, followed by water and necessary auxiliary agents. A pulp fiber slurry is produced by adding the agent and stirring and mixing, and a desired amount of this pulp fiber slurry is fed into the mold surface located at the lower part of the above-mentioned closed cylinder and accommodated therein, and then the inside of the closed cylinder is at atmospheric pressure. It is characterized in that the pulp fiber sludge is strongly pressed onto the mold surface while being kept in a higher pressure atmosphere, and at the same time, it is permeated from the water passage mold and drained, thereby forming a layered molded product of pulp fiber on the mold surface. It is a thing.

Now, in order to speed up the understanding of the method of the present invention, a description will be given based on an example, but first, an apparatus will be shown.

It should be noted that the configuration of the embodiment apparatus is shown in FIGS.
5 and 6 show a molded layered product.

In FIG. 1, a rail 4 for guiding inner and outer movements is provided at a lower portion of a closed cylinder 3 which connects a raw material supply pipe 1 and a pneumatic feed pipe 2 to an upper portion, and a lower opening portion of the closed pipe 3 is provided above the rail 4. The holding frame 5 is provided so as to move inwardly to come into close contact with and to move out of the closed cylinder 3, and the water passing mold 6 formed in a required shape is fixed to the holding frame 5.

A drainage port 7 is provided on the rail 4 so as to correspond to the lower opening of the closed tube 3, and a drainage receiving tube 9 to which a drainage pipe 8 is connected is provided below the drainage port 7.

In addition, the water-passing mold 6 generally has a structure in which a wire mesh mold having a concavo-convex shape is stretched on a base frame, or a metal mold manufactured by concavo-convex having a desired shape is provided with a large number of small holes. Target.

However, it is not limited to the above structure, and any type may be used as long as it has a structure in which pulp fibers do not pass and only water is excessively discharged.

Therefore, the water-passing type 6 is slid on the rail 4 by sliding the holding frame 5.
Is moved so as to match the lower opening of the closed cylinder 3.

In FIG. 2, the water passage mold 6 is brought into close contact with the lower opening of the closed tube 3, and in this state, the closed tube 3 is closed.
A desired amount of pulp fibers that have been crushed, defibrated, and dried via the raw material supply pipe 1 inside, and a required amount of liquid synthetic resin,
A necessary amount of the flame retardant is fed and air is sucked from the air pressure feeding pipe 2 to maintain the inside of the closed cylinder 3 in a reduced pressure atmosphere lower than atmospheric pressure.

At this time, of course, the opening / closing valve (not shown) of the drainage pipe 8 is closed to cut off communication with the outside.

Due to the reduced pressure atmosphere, the liquid synthetic resin and the flame retardant are quickly absorbed and impregnated in the pulp fibers fed into the closed tube 3.

After that, the pulp fiber is discharged to the outside by opening the drainage pipe 8, preheated to fix the synthetic resin and the flame retardant to the pulp fiber, and then an appropriate amount of water and a necessary auxiliary agent are added and mixed and stirred. Pulp fiber sludge P is produced.

Then, again, an appropriate amount of pulp fiber sludge P (hereinafter referred to as sludge P) is fed into the closed cylinder 3 through the raw material supply pipe 1, and the sludge P is placed on the water-passing mold 6 in a standby state.

Therefore, the raw material supply pipe 1 is closed after supplying a required amount of the sludge P to the inside of the closed cylinder 3, and high pressure air is sent into the inside of the closed cylinder 3 by the air pressure feeding pipe 2.
By injecting high-pressure air into the inside of the, the internal pressure is increased, and the sludge P is pressed against the water-passing mold 6 at high pressure.

Therefore, the sludge P is separated into pulp fibers and water, the water permeates through the water passage type 6 and is dehydrated from the drainage port 7 and the drainage receiving cylinder 9 to the drain pipe 8, and the pulp fibers are on the surface of the water passage type 6. A layer is formed while being pressed down with strong pressure.

And in FIG. 4, the water-permeable mold 6 has escaped by sliding the holding frame 5 outward from the lower opening of the closed cylinder 3, and the water-permeable mold 6 has a molded body made of a layer of pulp fibers. When A is attached and the molded body A is separated from the water-permeable mold 6 by a suction method or any other known method, a molded body A having the shape shown in FIGS. 5 and 6 is formed.

The molded product A released from the water-passing mold 6 is still in a water-containing state, and is completely compressed by pressing or compressing in the subsequent steps, utilizing a heat drying method, or performing a sun drying method. It is dried and made into a product.

When a synthetic resin is used, it is most suitable to be a liquid such as a condensate of a phenolic resin under normal temperature and normal conditions, but a solution or suspension of a synthetic resin dispersed or dissolved in water or an organic solution. It may be a suspension.

When the flame retardant is used, it is generally a phosphoric acid-based chemical liquid such as condensed ammonium phosphate solution,
Regardless of the type, it is necessary to select one with low specific gravity and low viscosity.

Effects and Effects of the Invention According to the method of the present invention, in order to impregnate the pulp fiber with the synthetic resin and the flame retardant in advance by the depressurization method in producing the pulp fiber sludge, the pulp fiber is sufficiently penetrated into the inside, and further, in water. Even when mixed into sludge, the fibers and synthetic resin or flame retardant are completely released, and the uneven distribution is completely eliminated, and the effect is evenly exerted on all pulp fibers, resulting in outstanding performance overall. Further, when the molded body is heated, in the case of the synthetic resin, the contact points of the fibers are entangled and fused with each other to reinforce the structure of the layer, and the tensile strength is improved. Even in the case of a flame retardant, the effect is widespread and the flame retardancy can be reassured.

[Brief description of drawings]

1 to 4 are partially vertical front views showing steps of an apparatus for explaining a molding method of the present invention, and FIG. 5 is a perspective view of a hollow body molded by the same apparatus, FIG. FIG. 6 is a vertical sectional front view of the molded body of FIG. 5. A ... Molded body, 1 ... Raw material supply pipe, 2 ... Air pressure feeding pipe,
3 ... Airtight cylinder, 4 ... Rail, 5 ... Holding frame, 6 ... Water passing type, 7 ... Drain port, 8 ... Drain pipe, 9 ... Drain receiving cylinder, P
... Pulp fiber sludge

Claims (1)

(57) [Claims] 1. A closed cylinder is provided so as to cover the upper surface of a water-permeable type mold which can be discharged, and pulp fibers crushed and defibrated and dried in the closed cylinder, and a required amount of liquid synthetic resin and flame retardant. Liquid synthetic resin and flame retardant are impregnated in the pulp fiber by keeping the inside of the closed cylinder at a reduced pressure atmosphere lower than the atmospheric pressure, and then the pulp fiber is taken out from the closed cylinder and subjected to preliminary heat treatment, followed by water and Pulp fiber sludge is produced by adding the necessary auxiliaries and mixing, and after sending the required amount of this pulp fiber sludge onto the mold surface located at the bottom of the above-mentioned closed cylinder, the inside of the closed cylinder is enlarged. It is characterized in that the pulp fiber sludge is strongly pressed onto the mold surface while being kept in a high pressure atmosphere higher than atmospheric pressure, and at the same time, it is permeated from the water passing mold and drained, thereby forming a layered molded product of pulp fiber on the mold surface. Pulp fiber pressure molding method.