JPS5954017B2 - Manufacturing method of polyurethane foam chip material using polyurethane prepolymer alone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyurethane foam chip material using a single polyurethane prepolymer.

The conventional method for producing chip foam using urethane scraps is to mix a prepolymer with chipped polyurethane foam and mold it. The viscosity is reduced to a certain level and then injected into the urethane chip and mixed.

Moreover, when the reaction of the prepolymer is completed, the triol and the like evaporate, resulting in many disadvantages such as physical properties, reaction time, and odor. To explain in more detail the manufacturing process of polyurethane foam chips, which has been commonly used up until now, with reference to the manufacturing process diagram in Figure 1, first, polyurethane foam scraps are crushed into 5m/mφ to 20m/mφ using a crusher, etc. It is crushed into chips and uses prepolymer as an adhesive medium.

The prepolymer manufacturing method is tolylene diisocyanate or methylene diisocyanate (including mixed products).
Add polyether or polyester such as polyprene glycol with about 1,000 to 3,000 molecules to the unreacted NC.
60℃ in a tank etc. to have about 5 to 50% O group.
It is manufactured by controlling the temperature to ~90°C and mixing for 1 to 3 hours. The main chemical reaction is the urethane bond ~0H+0CN~→N-C-0~ Here, 5-50% of unreacted NCO groups is obtained by adding more equivalents of 0CN~ to the equivalent of ~0H. It is a prepolymer containing a polymer compound with urethane bonds of ~0H and 0CN~ and tolylene diisocyanate having an unreacted NCO group.

Naturally, there is also a chemical reaction with water, and the chemical formula is ~NCO-lHs4-I-OCN→N-C-N~+CO
2 In this way, tolylene diisocyanate is highly reactive and reacts with moisture in the air.

Therefore, the reactivity is temporarily lowered by diluting it with a triol or the like that does not have ~0H (hydroxyl group).

This prepolymer is added to the urethane chip at a weight ratio of 5 to 50%.
degree, 2 with a gear pump and air spray gun
Inject by applying pressure of kg/cm2 to 7 kg/cm2.

At this time, the viscosity of the prepolymer alone is approximately 1000 to 20
, 000 cps, and in conventionally used gear pumps and air spray guns, the particles of the prepolymer during the injection time are relatively coarse, and the miscibility with the urethane chips is poor, making it difficult to obtain stable quality. Therefore, in order to lower the viscosity of the prepolymer, heating and insulation (
The viscosity is controlled by heating (30 to 50°C) or adding a triol or the like to make the particles of the prepolymer relatively fine at the time of injection, and the mixture is injected and mixed for 3 to 6 minutes.

Then, it was further injected into block molds and molds, and 3 to 12
Molding reaction takes place through min.

It is then removed from the mold, dried, and made into a product. The above is the conventional manufacturing method of urethane chip foam that has been carried out to date.
Is the injection, mixing time and steam passing time relatively long?
It is inferior in terms of workability, generates a lot of odor, and has a large impact on workers.Also, due to the deterioration of mixability, physical properties such as tensile strength and tear strength are inferior, making it impossible to obtain stable and excellent quality. There were various drawbacks.

In view of the above, the present invention provides a method for producing a polyurethane foam chip material that does not use any triol or the like, as will be described below, to solve the above-mentioned deficiencies of the prior art.

The method for manufacturing polyurethane foam chips of the present invention will be explained in detail with reference to the manufacturing process diagram shown in FIG. 2.

Since the urethane chip foam manufacturing method of this invention does not use any triols, the prepolymer has strong reactivity and high viscosity. Although there were many problems that could not be solved, this invention first avoids contact with air in the mixing tank, feed piping, etc. during the production of the prepolymer, and utilizes the reaction heat generated during the production of the prepolymer. By adding heat insulation at 60℃. The viscosity is lowered to some extent from 1000 to 5000 CPS.

In addition, as for the injection method, since the viscosity of the prepolymer is high and it is not possible to supply it consistently with a conventional gear type gear pump, we have switched to a piston type pressurized pump and used an air''-spray gun at 5.
It can withstand high pressures of 0 to 1000 kg/Cnl2, and the nozzle hole diameter has been changed from the conventional 2 to 5 m/m to 0.1 to 1.5 m/m.
In addition, the nozzle hole shape was changed from circular to flat circular so that fine particles can be sprayed in a wide range of shapes, reducing the injection and mixing time from 4 to 5 minutes to 40 to 50 seconds. Improved.

Furthermore, since the reactivity of the prepolymer is too high, the reactivity is lowered by using triol, etc. The problem that it was necessary to keep the mixture for a long time could be solved by shortening the injection and mixing time to 4 to 50 seconds. Then, the prepolymer is injected,
Inject the mixed urethane chips into a block mold or mold at a pressure of 3 kg/Arlt to 7 kg/Cnl.
Apply steam from Step 2.

In this case, in the case of the conventional block type, 10 to 12 mi
n, but it can be shortened to 5 to 6 minutes, and here too, the time can be shortened to about 1/2, contributing to energy saving. This is a manufacturing method in which a molding reaction is carried out, and the product is then removed from the mold and dried.

According to the manufacturing method of the present invention, physical properties such as tensile strength and tear strength are improved by about 1% compared to conventional urethane chip foams by improving mixability without using triols or the like.
It rose by a certain amount.

As mentioned above, the method for manufacturing polyurethane foam chips using a single polyurethane prepolymer according to the present invention does not use triols at all, so the injection, mixing time, and water vapor passage time can be shortened, resulting in good workability and efficiency. It is highly effective, generates little odor, and has little impact on workers.

In addition, it has good mixability, excellent physical properties such as tensile strength and tear strength, and excellent quality, and has excellent stability and outstanding effects. In the present invention, the reactivity of the prepolymer was so high that it was necessary to lower the reactivity with triol, etc., but in this invention, the reactivity of the prepolymer was injected at high pressure into fine particles using a piston type pressure pump. By mixing, this problem could be solved without using triol or the like.

As described above, the present invention is a method of manufacturing urethane chip foam using a single prepolymer, which is a creation of a new and advanced technical idea that is improved over the conventional method of manufacturing urethane chip foam.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a manufacturing process diagram of a conventional urethane chip foam block, and FIG. 2 is a diagram of a manufacturing process of a urethane chip foam block according to the present invention.

Claims (1)

[Claims] 1 When molding polyurethane foam scraps into chips, solvents that do not have hydroxyl groups such as triol and methylene chloride (
A polyurethane foam chip material is produced by spraying and mixing polyurethane prepolymer (hereinafter referred to as prepolymer) alone into fine particles through a fine nozzle hole at high pressure with a piston-type pressurized pump without using any triol (hereinafter referred to as triol, etc.). A method for producing a polyurethane foam chip material using a single polyurethane prepolymer, which is characterized by molding.