JPS59158235A - Preparation of polyurethane molded article in mold of which at least one surface is formed of concrete - Google Patents

Abstract

PURPOSE:To prepare the titled molded article having good adhesive effect, by supplying a stock solution having air mixed therein and a stock solution free from air to an injection molding machine to mix both of them while injecting the resulting mixture into a mold of which at least one surface is formed of concrete. CONSTITUTION:The polyurethane stock solutions stored in tanks T1, T2 are recirculated through an emitting pipe P, a heat exchanger H1, an emitting pipe P1, a change-over unit 2, a bypass P3 and a tank pipe P2 while air is supplied to the stock liquid in the tank T2 to control the viscosity thereof. Subsequently, a needle valve 13 is operated to open the jet path 16 of an injection molding machine R and the stock solutions in the tanks T1, T2 are injected toward an emitting passage 17 to mix both of them while the resulting mixture is injected in a mold 3 of which at least one surface is formed of concrete to adhere a polyurethane molded article to the concrete surface.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a polyurethane molded product using a mold that rivets.

For example, as shown in FIG. 1, a molded product may be produced in which the lower surface or surrounding area of concrete sleepers (al) is wrapped with polyurethane (b).

In that case, one side of the mold is made of concrete, but concrete has countless unevenness and moisture on its surface, and the overall surface is flat like a metal mold. does not have.

When using such a special material as at least one side of the mold, the polyurethane stock solution must be mixed very well, otherwise it will be difficult to bond it uniformly to the concrete surface. .

In many cases, old raw materials contain a mixture of the same phase and liquid phase at room temperature, which requires extremely strict quality control.

The present invention has been made to address these points, and is based on polyurethane that exhibits good adhesion to the concrete surface when a part of the mold is entirely made of a foreign material such as a concrete surface. The purpose is to provide a method for manufacturing molded products.

Next, an example will be described.

<A> Overall configuration (Figure 1) The discharge valve (P+) connected to the outlet of the first tank (TI) has a pressure pump (P) and a heat exchanger (i (,) interposed in the middle. After that, it is connected to the inflow port (11) of an injection molding machine (hereinafter referred to as RIM) (R).

Furthermore, connect the IRIM(R) paste to the tampon (12), or connect the tampon (P2) other end to the first tank (Tl).
) is connected to the return port.

A circuit similar to the above is connected to the second tank (T2) and
).

That is, in the embodiment, two sets of circuits are connected to one RIM(R).

<Port> Auxiliary mechanism Each tank (Tl) (T2) is equipped with a heating device,
Furthermore, each pipe group (PI) (P2) is also provided with a heating device such as a hot water pipe or an electric heater.

The heat exchanger (H) lowers the temperature of the superheated liquid.

Further, an air mixer (A) is installed on one or two of the discharge tubes (PK), and the viscosity of the stock solution is adjusted by mixing air in an appropriate ratio to the stock solution.

<NO'> Structure of RIM (Figures 2 and 3) RIM (R) Fi has a needle valve (13) in the center, and on both sides there are inlet ports (11) and return ports (11).
2) and one set each.

And the inflow port (11) (12)
A jetting passage (14) is branched in the middle of the liquid passage connecting the two, and a rotary valve (15) is located at the branching point.

The two sets of jet and outlet passages (14) are opened toward the needle valve (13), but the outlet has an oriice (16).
position.

The rotary valve (15) has a pinion (17) fixed on its shaft, and a rack (18) that moves up and down together with the needle valve (13).
) causes the pinion (17) to reciprocate and rotate.

When the needle valve (13) operates and becomes open, 2
The outlets of the set of ejection passages (14) open toward one ejection passage (19)K at the same time.

The orifice (16) is a disc as shown in Figure 1, and around it is a torsion groove (
16a) are engraved in plural pieces.

Furthermore, by reversing the directions of the torsion grooves (i6a) of the orifices (16) positioned opposite to each other, 2f
The A and B liquids ejected from the tl'l ejection path (14) rotate in opposite directions and collide with each other, resulting in poor mixing.

) Bypass Connect each discharge pipe (P+) to the intake pipe (P2) with a bypass pipe (Ps).

A high/low pressure switching unit (2) is positioned in the center of the bypass pipe (Ps).

This unit (2) is switched by valve operation to allow liquid to pass through when the pressure is low, and to close the circuit and supply the liquid eRIM(R) when the pressure is high.

In addition, the throttle valve (21) installed in the high/low pressure switching unit (2)
The purpose of this is to maintain a heat-retaining state by constantly circulating the liquid to RIM(R) with a certain degree of resistance.

G) Mold The mold (3) is a conventional mold made of metal around the mold, but in particular, at least almost one side is covered with a concrete product, such as a concrete sleeper (31).

The purpose of this invention is to manufacture concrete sleepers partially coated with polyurethane, but the purpose of use of the present invention is of course not limited to this.

Next, the operation will be explained.

<B> Characteristics of the stock solution A liquid stored in the first tank (TI) and the second tank (T2)
The method of the present invention is particularly effective when there is a difference in activity between liquid B and liquid B.

<Port> During circulation, the stock solution from each tank (Ts) (T2) continues to circulate through the bypass (Ps)k via the switching unit (2) in the open state.

(n) When the needle valve (13) operates during injection into the mold, the ejection path (1
When the end of 4) is opened, the stock liquid is ejected through the orifice (16) toward the instantaneous discharge passage (17), liquids A and B are mixed, and the mixed liquid is discharged from the discharge passage (17). Injected into mold (3).

Since the present invention is as described above, the following effects can be expected.

<B> The two ejected liquids collide while rotating in opposite directions, so they are mixed very well.

Therefore, even if the polyurethane layer adheres to a concrete surface that has a rough surface and contains moisture, the reaction will occur uniformly, and the polyurethane layer and the concrete will be completely and evenly bonded over the entire contact surface.

<Exposure> The viscosity of the liquid decreases because air is completely mixed with the stock solution in the middle. As a result, it is possible to quickly develop the reaction even on uneven surfaces of concrete, and to perform a uniform and good reaction.

[Brief explanation of the drawing]

Figure 1: An explanatory diagram of an embodiment of the circuit used in the method of the present invention. Figure 2: An exploded view of the main parts of an injection molding machine. Figure 3: A perspective view of orifice parts of an injection molding machine. Figures 4 and 5: Explanatory diagram of the operating state of the injection molding machine P1: Discharge pipe, R: Injection molding machine, P2: Retan Paizo, 13:
Two-dollar valve, 14: Spout passage, 15: Rotary valve, 16: Orifice Applicant: Nisshin Boseki Co., Ltd. Figure 5 R Procedural Amendment May 22, 1981 Director-General of the Special Federal Reserve Agency Kazuo Wakasugi 1. Description of the case 1982 Patent Application No. 32211 2 Title of the invention Method for manufacturing polyurethane molded products in molds in which at least one side is molded with concrete 3 Relationship to the case of the person who created Nyama Tadashi Patent applicant address 3-10 Nihonbashi Yokoyama-cho, Chuo-ku, Tokyo Name
Nisshinbo Co., Ltd. Representative Rihan Nakao 4, Agent 105 Address 9F5 Marufuji Hill, 3-1-10 Shinbashi, Minato-ku, Tokyo, Date of amendment order Voluntary 6, Amendment pair 9 171-

Claims (1)

[Claims] Two sets of heated stock solution tanks and circulation pipes are provided, and f'L
are connected to one injection molding machine, air is mixed into the stock solution in the middle of the circulation pipe and the pipe is kept warm, the stock solution is rotated and mixed in the injection path of the injection molding machine, and the mixed solution is spread over at least one surface. A method for producing a polyurethane molded product in a mold having at least one side made of concrete, the method comprising pouring into a mold made entirely of concrete.