JPH0225937B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyurethane foams, and in particular to a method for producing elastic foams obtained by introducing various fillers into the foams in a novel manner. Elastic foams, such as polyurethane foams, are made by reacting organic isocyanates with polyether polyols or polyester polyols using water as a blowing agent, and are produced using the one-shot method, which is a one-step foaming reaction, and the two-step foaming reaction. The prepolymer method is well known. By the way, in the production of such urethane foam, various fillers are mixed during the production process in order to modify the physical properties of the resulting foam. As the modifying material used here, thermoplastic resins having high frequency heat fusion properties and others are used. However, in the conventional manufacturing process, these modifiers are mixed with the polyol in the raw materials used.
In some cases, after the foam is produced once, the foam is impregnated into the foam in a subsequent step. This is because organic isocyanate, which is one of the two main raw materials for urethane foam production, is extremely toxic and is unfavorable for the process when mixing foam modifiers into it, and organic When a foam modifier is mixed into isocyanate, the amount increases accordingly, which not only causes the disadvantage of increasing the amount of toxic substances that are difficult to handle, but also causes an imbalance in the reaction between organic isocyanate and polyol. This is because it was predicted that it would not be possible to obtain a foam having uniform microbubbles.

The inventors of the present application have already been engaged in the production of polyurethane foam for 20 years, and during that time they have produced urethane foam mixed with various fillers.
The manufacturing method is the same as other people skilled in the art, either by mixing a filler into the polyol in advance and bringing it into contact with isocyanate, or by creating a foam and then filling it with a flame retardant or other modifier. The method was adopted.

However, mixing a foam modifier into polyol will further increase the viscosity of the polyol, and there is a limit to the amount of foam modifier added.
This has been pointed out in the past. Therefore, those skilled in the art had no choice but to impregnate the obtained foam with a modifying material in a post-process, but this method resulted in an increase in the number of man-hours and significantly increased costs. Therefore, the inventors conducted repeated experiments from all angles without being bound by conventional wisdom, and found that the modifier filled in polyurethane foam does not necessarily have to be mixed with polyol, contrary to conventional wisdom. I have found that there is no reason why this should not be the case. As we continued to experiment, we discovered that there was no particular difficulty in mixing and stirring the modifying material into the highly toxic organic isocyanate, and what was particularly important was that it was possible to react the modifier with the polyol to create bubbles. It was discovered that manufacturing the body brings about various unexpected effects, such as making it possible to introduce a large amount of filler to the outside, and has now completed this invention. That is, the present invention provides a polyol,
When producing a flexible polyurethane foam by mixing and stirring raw materials for polyurethane foam containing an organic isocyanate and at least a blowing agent, silicone oil, amine catalyst, and tin catalyst, powdered thermoplastic is added to 100 parts by weight of the organic isocyanate. 60 ~ foam modifier made of at least one type of resin
This method of producing polyurethane foam is characterized by mixing 800 parts by weight, stirring, mixing polyol and other raw materials, and foaming. This invention will be further explained below.

The main raw materials used in this invention are exactly the same as those for conventional urethane foam, and are organic isocyanate and polyol. Water is used as a blowing agent, and catalysts such as tin and amine are also used. In the present invention, first, a predetermined amount of a powdered thermoplastic resin foam modifier is mixed into an organic isocyanate, that is, 60 to 800 parts by weight per 100 parts by weight of the organic isocyanate, and the mixture is stirred to be sufficiently uniformly dispersed or dissolved. let
If the amount of the powdered thermoplastic resin as a modifier added is less than 60 parts by weight, a sufficient foam modification effect cannot be expected, and if it exceeds 800 parts by weight, good foams cannot be obtained. Examples of the powdered thermoplastic resin of the foam modifier used here include polyethylene resin, polypropylene resin, polystyrene resin, vinyl chloride resin, acrylic resin, vinyl acetate resin,
Examples include nylon. Although these modifying materials themselves have been known for a long time, and some of them are actually used, there is no technology to use them by mixing and stirring them with organic isocyanates in advance, and in this respect, the present invention can be said to be a completely new technology. In the present invention, the above-mentioned modifiers are mixed with an organic isocyanate having a low viscosity, so that these modifiers are well dispersed or dissolved in the isocyanate, making it possible to mix and stir a large amount of the modifier. All conventional modifiers were mixed with high viscosity polyols, which limited their agitation, and the amount was usually 20 to 40% by weight, and at most 50 to 60% by weight, based on 100 parts by weight of polyol. However, in the present invention, although it varies depending on the type of modifier, it is possible to mix up to 800% by weight when converted to 100% by weight of polyol. In the present invention, the method of mixing the above-mentioned modifying material into isocyanate is to store the isocyanate in a stirring tank equipped with a stirring blade in advance, add the specified modifying material therein, stir it thoroughly, and then pump it through a pipe. All you have to do is guide it to the mixing head, and no special measures are required. According to the present invention, it is possible to add a large amount of the modifier to the isocyanate as described above, but despite the addition of such a large amount of the modifier, the subsequent reaction with the polyol is carried out uniformly and the cell A major feature of the present invention is that roughness and non-uniform foaming do not occur. The inventors have endeavored to investigate the cause of this problem, but it has not yet been completely clarified. However, based on the results of various experiments to date, the behavior is that the isocyanate and the various modifiers mixed therein bond with each other as fine particles during stirring.
Isocyanate is applied to each fine particle of the modifier, which has poor reactivity, and these particles become integrated.
It is thought that these may interact chemically and react with the polyol in some cases. Therefore, according to the present invention, unlike conventional foams in which modifying material particles simply exist between the urethane bonds, the modifying material is introduced into the urethane bonds as if they were introduced into the urethane bonds. It becomes like a state. Therefore, according to the present invention, it is presumed that uniform foaming is achieved over a wide range, compared to a foam obtained by mixing the same amount of modifier into polyol and reacting it.

The organic isocyanate mixed with a predetermined amount of the modifier and stirred sufficiently uniformly is sent to a mixing machine along with polyol, water as a blowing agent, tin, amine, etc. as a catalyst, where all these raw materials are mixed. It is discharged from a discharge nozzle into a mold or other predetermined foaming mold, where it is foamed. In carrying out the method of the present invention, it goes without saying that not only the one-shot method but also the prepolymer method can be applied in exactly the same manner. Furthermore, various embodiments of the present invention are conceivable. For example, when using two or more types of modifiers, or even when using a single modifier, in addition to mixing the modifier with the isocyanate as described above, the modifier is also added to the polyol used therein. The method is to mix both at the same time as in the conventional method. This makes it possible to introduce the modifying material even more easily. Furthermore, it goes without saying that a modifier can be further introduced into the foam obtained by the present invention by dipping or other post-processing.

The structure of the present invention is as described above, and according to this, a large amount of various modifiers can be easily introduced into the foam, and a foam with various rich properties can be obtained. Instead, the obtained foam has uniform cells, and cell roughness and non-uniform foaming can be well avoided. Furthermore, in terms of quantity, there is no big difference from conventional products, and even if we focus on the case where a large amount of modifier is not mixed, when the present invention is used, the bubbles are made more uniform compared to when it is added to conventional polyol. can be achieved, and even though its density is lower than that of conventional products, its physical properties are equal to or better than those of conventional products. The present invention will be further explained below with reference to Examples.

Example 1 Polyether polyol with trifunctional molecular weight of 3000
100% by weight H ₂ O 4.0 Triethylenediamine 0.1 Normal ethylmorpholine 0.45 Silicone oil 2.0 Dibutyltin dilaurate 0.3 Resin powder for vinyl chloride paste 100 Tolylene diisocyanate 56 Among the above formulations, the resin for vinyl chloride paste was dispersed in tolylene diisocyanate. The mixture was then mixed, stirred and foamed using the one-shot method.

Stirring time: 10 seconds Cure time: 85°C x 15 minutes The resulting foam was uniformly foamed throughout.

Physical properties Specific gravity 0.039 Tensile strength (Kg/cm ² ) 0.45 Elongation (%) 55 Tear strength (%) 0.30 When this foamed product was sliced into 3 mm pieces and fused using high frequency, it became PVC leather at 0.2A x 8 seconds. It was well fused.

Example 2 Polyether polyol with trifunctional molecular weight of 3000
100 parts by weight H ₂ O 4.0 Triethylenediamine 0.1 Normal ethylmorpholine 0.4 Silicone oil 1.6 Dibutyltin dilaurate 0.25 Resin for vinyl chloride paste (powder) 30 Tolylene diisocyanate 56 Among the above formulations, the resin for vinyl chloride paste is dispersed in tolylene diisocyanate. After that (it looked like it had dissolved), it was mixed and stirred using the one-shot method to foam.

Stirring time 10 seconds Cure time 85℃ x 10 minutes Physical properties This method Comparative example Specific gravity 0.023 0.025 Tensile strength 0.95 0.78 Elongation 140 130 Tear strength 0.51 0.40 In the comparative example, the resin for vinyl chloride paste was dispersed in polyol in the above example. It is something.

Example 3 Trifunctional polyether polyol molecular weight 3000
100wt% H ₂ O 4.5 Triethylenediamine 0.15 Normal ethylmorpholine 0.50 Silicone oil 2.0 Dibutyltin dilaurate 0.3 Polystyrene (powder) 110 Tolylene diisocyanate 59.5 Mix and disperse polystyrene in tolylene diisocyanate, stir for 10 seconds using the one-shot method, and foam at 85℃ I cured for 15 minutes.

Density: 0.042 Hardness (Kg/JIS): 19.2 When 110 parts by weight of powdered polystyrene was mixed with polyether polyol, the viscosity increased significantly and foaming was impossible.

Example 4 Trifunctional polyether polyol molecular weight 3000
100wt% H ₂ O 3.7 Triethylenediamine 0.2 Triethanolamine 3.0 Silicone oil 1.5 Sternus octate 0.2 Nylon resin (powder) 40 Tolylene diisocyanate 51 Mix and disperse nylon resin in tolylene diisocyanate. Thereafter, the mixture was stirred for 10 seconds using the one-shot method to foam, and cured at 80°C for 15 minutes.

Comparative Example of the Present Invention Density 0.027 0.028 Tensile Strength 1.05 0.94 Elongation 155 140 Tear Strength 0.63 0.52 Thermal Adhesion Good Good The comparative example is one in which nylon resin (powder) is dispersed in polyol.

Example 5 Trifunctional polyether polyol molecular weight 3000
100wt% H ₂ O 4.0 Triethylenediamine 0.15 Normal ethylmorpholine 0.45 Silicone oil 2.1 Dibutyltin dilaurate 0.3 Nylon resin 150 Tolylene diisocyanate 56 Nylon resin was mixed and dispersed in 110wt% tolylene diisocyanate, and the remaining 40% was mixed and dispersed in polyol. Ta. The mixture was stirred for 8 seconds using the one-shot method to foam, and cured at 85°C for 15 minutes. The obtained foam had a density of 0.045 and was confirmed to have excellent high frequency characteristics.

When this foam was sliced into 3 mm pieces and fused using high frequency, it was successfully fused to PVC leather at 0.25 A for 5 seconds.

Example 6 Trifunctional polyether polyol molecular weight 3000
100wt% H ₂ O 4.0 Triethylenediamine 0.12 Normal ethylmorpholine 0.4 Silicone oil 1.7 Dibutyltin dilaurate 0.2 EVA (ethylene-vinyl acetate copolymer) 50 Tolylene diisocyanate 54.0 EVA resin is dispersed in tolylene diisocyanate, and then 10% by one shot method The mixture was stirred for seconds to foam and cured at 85°C for 15 minutes.

Density 0.028 Hardness (Kg/JIS) 14.2 Tensile strength (Kg/cm ² ) 1.08 Elongation (%) 138

Claims (1)

[Claims] 1. When producing a flexible polyurethane foam by mixing and stirring polyol, organic isocyanate, and other raw materials for polyurethane foam containing at least a blowing agent, silicone oil, amine catalyst, and tin catalyst, for 100 parts by weight of the organic isocyanate,
A method for producing polyurethane foam, which comprises mixing 60 to 800 parts by weight of a foam modifier made of at least one type of powdered thermoplastic resin, stirring the mixture, mixing polyol and other raw materials with the mixture, and foaming the mixture.