JP2003342343A - Foam having high impact resilience - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foam which can avoid a bottom-out phenomenon under a high load and can exhibit high impact resilience by using a polyol having a molecular weight above a certain value, a diphenylmethane diisocyanate (MDI), and a crosslinking agent having three or more functional groups. <P>SOLUTION: In a foam having high impact resilience, comprising a polyurethane resin obtained by mixing a polyol, an isocyanate and various additives, the polyol used has a molecular weight of 6,000 or higher, the isocyanate used comprises a diphenylmethane diisocyanate (MDI), and one of the additives used comprises a crosslinking agent having a functionality of 3 or higher, in an amount of 1-15 pts.wt. based on 100 pts.wt. of the whole polyol. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foam exhibiting a high impact resilience, and more particularly, it has a density of at least 70 kg / m ^{3 in} order to take advantage of the high impact resilience, which results in a bottoming phenomenon under load. The present invention relates to a high impact resilience foam capable of avoiding the above.

Generally, a flexible urethane foam is a material having a good cushioning property indicated by the impact resilience,
In addition, it has a feature that its physical properties can be easily designed depending on the types and amounts of additives such as polyols and isocyanates as main raw materials and crosslinking agents. As an example, HR (high resilience) foam, which has particularly high impact resilience, so-called high impact resilience foam, is used almost exclusively as a sheet material in the automobile field.

A high impact resilience foam suitable for use in automobile seats has an impact resilience of 60 to 65%.
The thing of about the level was used suitably. It has been generally known that when the high impact resilience foam is produced, the number of functional groups of the polyol is adjusted and tolylene diisocyanate (TDI) is used as the isocyanate. This is explained from the microstructure of the foam exhibiting high impact resilience, and the three-dimensional microstructure of the foam improves the three-dimensional mechanical strength such as the impact resilience. It is one of the raw materials for selectively forming a three-dimensional microstructure.

[0004]

By the way, recently, for example, as a material for a sole for shoes, which can reduce the load on the human body and effectively use kinetic energy,
The high impact resilience foam is employed. However, in the case of the sole, since a large load is momentarily applied, it is conceivable that the load causes the sole portion to be in a so-called bottoming state. In such a state, the sole cannot exhibit a high impact resilience, and the load input due to the bottoming phenomenon is output as a reaction to the human body, which causes a problem. It has been pointed out.

Such a problem can be avoided by preventing the bottoming phenomenon from occurring in order to exhibit the high impact resilience. Specifically, a method of increasing the thickness or increasing the density can be considered. However, in this case, the thickness that can be installed according to the intended use depends only on the place of installation, and it is difficult to deal with the same as in other automotive seat applications. In this case, the density of the high impact resilience foam is 50 to 60 kg / m due to a compositional problem for expressing high impact resilience, that is, tolylene diisocyanate (TDI) which is preferably used as an isocyanate. ³ was the upper limit. For example, by improving the so-called molding method for improving the overpack rate at the time of injecting the mold, the density of 20% is
It is possible to improve the degree, but it is difficult to respond further,
In addition, it is not practical because the manufacturing cost increases due to an increase in required equipment and raw materials used.

In addition to the above-mentioned method using the overpack ratio, for example, it is possible to increase the density by reducing the amount of the foaming agent or increasing the amount of the catalyst. However, in the former case, the production cycle time deteriorates due to a decrease in the amount of heat generated during foaming and curing of the polyols and isocyanates, which are the main materials, and in the latter case, various physical properties such as a decrease in heat resistance are caused. Since there is a concern that problems such as deterioration may occur, it is not suitable for adoption.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above problems of conventional high impact resilience foams, and is proposed in order to solve the problems, using a polyol having a molecular weight of a certain level or more and diphenylmethane. By using diisocyanate (MDI) and a cross-linking agent having three or more functional groups, the bottoming phenomenon that occurs when a high load is applied can be avoided and a high impact resilience can be achieved. It is intended to provide a rebound foam.

[0008]

In order to overcome the above-mentioned problems and achieve the intended purpose, the high resilience foam according to the present invention is obtained by mixing at least one polyol, isocyanate and various additives. In a high impact resilience foam made of a polyurethane resin, a substance having a molecular weight of 6000 or more is used as the polyol, and
Diphenylmethane diisocyanate (MDI) is used as the isocyanate, and a substance having a functional number of 3 or more is used as the crosslinking agent, which is one of the additives.
0 to 15 parts by weight, preferably 1
It is characterized in that the impact resilience is set to 65% or more at a density of 70 kg / m ³ or more by adding ˜15 parts by weight.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a high impact resilience foam and a method for producing the same according to the present invention will be described below with reference to the accompanying drawings with reference to preferred embodiments. The inventor of the present application uses a substance having a molecular weight of 6000 or more as the polyol, which is one of the main raw materials of the polyurethane resin, and uses a substance having three or more functional groups as the crosslinking agent, which is one of the additives. Achieving a high impact resilience of 65% or more and using diphenylmethane diisocyanate (hereinafter, referred to as MDI) as an isocyanate, a sufficient impact resilience as a high impact resilience foam is sufficiently expressed to 70 kg / m ³ or more. It was discovered that a high impact resilience foam capable of achieving a density can be obtained.

Basically, the polyurethane resin forming the high impact resilience foam is a reaction product obtained by polymerizing a required polyol and an isocyanate, and various kinds of the polyol and the isocyanate can be used by changing the kind of the polyol and the isocyanate. It expresses physical properties. The polyurethane refers to a polymer having a urethane bond, and the urethane bond is formed by an addition reaction between an isocyanate having an isocyanate group and a polyol having active hydrogen such as a hydroxyl group.

As the isocyanate, there is used MDI which has a high reactivity with the polyol due to its molecular structure and in which the resinification reaction takes precedence over the foaming reaction. Regarding the amount used, all isocyanates are MDI
However, it is sufficient that the MDI is mixed at a ratio of at least 40 parts by weight when the total isocyanate is 100 parts by weight. Further, by mixing 40 parts by weight of the MDI, it is possible to carry out the production without reducing the cycle time and the like even when using a high-reactivity polymer polyol described later.

When the mixing ratio of the MDI is less than 40 parts by weight, a high molecular weight polyol having a molecular weight of 6000 or more (described later)
The reactivity with [0016]) cannot be sufficiently ensured, which makes it unsuitable for mass production. At the same time, it is difficult to obtain a sufficient density, but this can be dealt with by increasing the amount of the catalyst mixed as an additive, as described later ([0021]).

Isocyanates other than MDI are usually obtained by modifying various aromatic, aliphatic or alicyclic isocyanate compounds having two or more isocyanate groups, and further modifying the isocyanate compounds. A modified isocyanate can be used, and two or more kinds of the isocyanate may be used in combination.
Specifically, crude diphenylmethane diisocyanate,
Tolylene diisocyanate (hereinafter referred to as TDI), naphthalene diisocyanate (NDI), P-phenylene diisocyanate (PPDI), xylene diisocyanate
(XDI), tetramethylene diisocyanate (TMXD
I), aromatic isocyanate such as tolidine diisocyanate (TODI), isophorone diisocyanate (IPD)
I), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H ₆ XDI), hydrogenated MDI (H ₁₂ MDI)
And alicyclic isocyanates such as hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), and lysine triisocyanate (LTI). Examples of the modified product include urethane modified products of isocyanate compounds, dimers, trimers, carbodiimide modified products, allophanate modified products, burette modified products, urea modified products, and prepolymers. Of these, TDI is particularly preferable because it is inexpensive. When the mixing ratio of TDI or the like other than MDI is 60 parts by weight or more in the total isocyanate, the impact resilience can be further improved, but in that case, the reaction temperature of the polyol and the isocyanate is 60%. It is necessary to improve the curing property by keeping the temperature above ℃.

In general, since MDI has a linear molecular structure, it has a shape bent at a constant angle, that is, a three-dimensional shape, such as TDI, which is preferably used as a raw material for a high resilience foam. Not not. Therefore, the mechanical strength due to the three-dimensional structure such as the impact resilience is inferior, while the mechanical strength due to the two-dimensional structure, such as tensile strength and tear strength, is improved. Have Also, due to its molecular structure, it is highly reactive with polyol, which is one of the main raw materials for obtaining polyurethane resin,
Furthermore, the resinification reaction is more predominant than the foaming reaction due to its low reactivity with water. For this reason, a large number of microscopically fine bubbles are generated, and the resin is promptly made into a resin, which has a characteristic that the density thereof becomes high. It should be noted that the high-resilience foam obtained by this rapid resinization also has a structural feature that the internal cells are finer and the cells are broken to have higher air permeability than the foam obtained from TDI as a raw material. Have

Therefore, when TDI, which has been conventionally suitably used, is used alone as the isocyanate, the foaming reaction becomes dominant and the above-mentioned density of 70 kg / m ³ or more cannot be achieved. Further, in the present invention, since the impact resilience of 65% or more can be secured regardless of the type of isocyanate by using a polyol or the like described later ([0016]), as described above, the total amount of all isocyanates may be MDI. No problem.

On the other hand, a compound having two or more hydroxyl groups is generally called a polyol, and as a polyol which can be preferably used in the present invention, a polyalkylene polyol having a hydroxyl value of 5 to 35 and an unsaturation degree of 0.07 mmol / g or less, etc. And one or more of these polyols are used.
Moreover, the molecular weight of the polyol is required to be 6000 or more. This molecular weight is one of the factors for achieving the impact resilience of 65% or more. In general, when the molecular weight becomes large, the reactivity may be decreased correspondingly, and the foaming and curing due to the reaction with the isocyanate component may be hindered. However, in the case of the present invention, MDI having high reactivity is used as the isocyanate. It doesn't matter.

As to the physical properties of the polyol, those having a hydroxyl value in the range of 5 to 35 and a low degree of unsaturation of 0.07 mmol / g or less are preferable, as described above. The hydroxyl value is the degree of reactive hydroxyl groups that effectively act on the reaction per 1 g of polyol, and this value is 5
If it is less than 1, the workability and the like will decrease due to the increase in viscosity and the like,
Further, if it exceeds 35, the impact resilience is deteriorated, which is not preferable. The degree of unsaturation is the degree of bond end that can cause a so-called polymerization reaction, and the lower the value, the higher the purity of the polyurethane resin foam. Therefore, when the degree of unsaturation is high, the number of urethane bonds formed by the reaction with MDI is reduced, and the density increase due to resinification is hindered, resulting in low density.

As the main polyol which is the main raw material of the polyurethane resin, in addition to the above polyalkylene polyol, for example, polyol such as polyester polyol, hydroxyl group-containing polydiene, polymer polyol in which fine particles such as addition polymerization polymer or condensation polymerization polymer are dispersed, and the like. The so-called sub-polyol may be added. Particularly in the case of the high-resilience foam according to the present invention, a graft polyol capable of promoting continuous foaming and improving hardness is suitable as the sub-polyol.

Examples of the additives include catalysts as polymerization initiators used in the production of ordinary polyurethane resins, crosslinking agents and foaming agents, and, if necessary, chain extenders, flame retardants or ultraviolet absorbers, and antioxidants. Agent, anti-aging agent, filler,
Examples include plasticizers, colorants, antifungal agents, antibacterial agents, and the like, and these auxiliary materials are added as necessary. For example, a polyvalent amine such as diethyltoluenediamine or dimethylthiotoluenediamine is used as the chain extender, and tris-dichloropropylphosphate, tris-chloroethylphosphate, dibromoneopentyl alcohol, tribromoneopentyl is used as the flame retardant. Alcohol, etc.
The UV absorber may be 2- (2-hydroxy-5).
-Tert-butylphenyl) benzotriazole,
2 '-(2'hydroxy-3', 5'-ditertiarybutylphenyl) 5chlorobenzotriazole, bis (2,2,2
6,6-Tetramethyl-4-piperidine) sepacate, 4
Examples thereof include benzoyloxy-2,2,6,6-tetramethylpiperidine and the like.

As the catalyst, it is possible to use a conventionally known substance, for example, dimethylcyclohexylamine, N-methyldicyclohexylamine, triethylamine, tripropylamine, tributylamine, N-.
Non-reactive monoamines such as methylmorpholine, N-ethylmorpholine and N-dimethylbenzylamine, triethylenediamine, tetramethylhexamethylenediamine, bisdimethylaminoethylether, tetramethylpropanediamine, dimethylaminoethylmorpholine, tetramethyl Non-reactive diamines such as ethylenediamine, diazobicycloundecene, 2-methyl-1,4-diazo (2,2,2) bicyclooctane, non-reactive triamines such as pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, dimethylethanol Reactive amines such as amines, N-trioxyethylene-N, N-dimethylamine, N, N-dimethyl-N-hexanolamine or organic acid salts thereof, 1-methylimidazole, 2-methylimidazole Imidazole compounds such as 1,2-dimethylimidazole, 2,4-dimethylimidazole, 1-butyl-2-methylimidazole,
Organic metal compounds such as stannas octoate, stannas oleate, didutyltin dilaurate, dibutyltin dimaleate, lead octylate, 2,4,6-tris (dimethylaminomethyl) phenol, 2,4,6-tris Examples of the trimerization catalyst include (dimethylaminoalkyl) hexahydro-S-triazine, potassium acetate, potassium octylate, and potassium 2-ethylhexanoate.

The amount of the catalyst added is basically in accordance with the production of a conventionally known foam made of a polyurethane resin, and the amount thereof is 0.1 with respect to 100 parts by weight of the total polyol. It is set to 01 to 10 parts by weight. If the amount added is 10 parts by weight or more, the reactivity between the polyol and MDI becomes excessive, which adversely affects the hardness of the finally obtained high impact resilience foam. However, when it is unavoidable to use a high molecular weight polyol having a molecular weight of 6000 or less as the polyol or MDI of less than 40 parts by weight with respect to 100 parts by weight of all isocyanates due to problems in physical property design and manufacturing process, the catalyst of It may be possible to deal with the problem by increasing the addition amount. In addition, it should be noted that the reaction between the above-mentioned polyol and MDI is completed in a short time, which makes it difficult to mix and adjust the raw material system and is not suitable for actual production.

The cross-linking agent has three or more polyfunctional groups forming a three-dimensional structure, that is, a three-dimensional structure when it becomes a part of a polyurethane resin which becomes a high impact resilience foam by a reaction, for example, diethanolamine. Alternatively, substances such as triethanolamine are suitable. The use of such a cross-linking agent is one of the important factors for achieving the impact resilience of 65% or more, like the above-mentioned polyol. In addition to this, for the high impact resilience foam finally obtained,
When considering the achievement of so-called two-dimensional improvement in mechanical strength such as tensile strength, in addition to the cross-linking agent having three or more polyfunctional groups described above, its molecular structure such as ethylene glycol is linear, That is, a two-dimensional crosslinking agent may be used. Specifically, polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, glycerin, trimethylolpropane, pentaerythritol, and sorbitol, amines such as hexamethylenediamine, hydrazine, diethyltoluenediamine, and diethylenetriamine, monoethanolamine. And amino alcohols such as diethanolamine and triethanolamine. Examples of the short molecular weight polyether polyol include substances having a hydroxyl value of 200 or more obtained by adding ethylene oxide and propylene oxide to the above crosslinking agents.

The amount of the crosslinking agent added is set in the range of 0.1 to 15 parts by weight, preferably 1 to 15 parts by weight, based on 100 parts by weight of all the polyols. It If the addition amount is less than 0.1 part by weight, it becomes difficult to achieve a repulsion elastic modulus of 65% or more even when the polyol has a molecular weight of 6000 or more. On the other hand, if the amount of the cross-linking agent added is 15 parts by weight or more, it has the effect of deteriorating the impact resilience that should be improved, so caution is required. This is also the case when the amount of water used as a foaming agent is excessive, but good phase separation between the hard segment and the soft segment is hindered as the concentration of urea groups in the obtained high-repulsion foam increases. This is because this causes movement inhibition of the soft segment. As the polyol,
When a material having a sufficiently low degree of unsaturation and a molecular weight of 12,000 is selected, the crosslinking agent is not always necessary. However, such a special polyol is not practical because its production is difficult.

As the foaming agent, water, HCFC-14
1b, HFC-134a, HFC-245fa or H
Halogenated hydrocarbons such as FC-365mfc, hydrocarbons such as cyclopentane, isopentane, normal pentane, nonafluorobutyl methyl ether, nonafluoroisobutyl methyl ether, nonafluorobutyl ethyl ether, nonafluoroisobutyl ethyl ether, pentafluoroethyl Hydrofluorocarbons such as methyl ether or heptafluoroisopropyl methyl ether, or liquefied carbon dioxide gas is used. Of these foaming agents,
Water is the most preferable in terms of versatility.

As described above, there is an upper limit ([0023]) to the amount of water added. It is empirically known that the amount is about 1 part by weight based on 100 parts by weight of all the polyols. In addition to water, various organic foaming agents can be used as the foaming agent. Also, the smaller the amount of water added, the better the density and the impact resilience can be exhibited.

As the foam stabilizer, substances generally used in the production of ordinary polyurethane foam can be used. For example, various foam stabilizers such as dimethyl siloxane type, polyether dimethyl siloxane type and phenylmethyl siloxane type are listed. The upper limit of the amount of addition is 3 parts by weight based on 100 parts by weight of all polyols. If the foaming condition is good, it is not necessary to add it.

The high impact resilience foam made from the above composition may have both high density and impact resilience, unlike conventional high impact resilience foams. Therefore, it is possible to efficiently avoid the phenomenon of bottoming which occurs when a large load is applied to the high-rebound resilience foam or when a sufficient thickness of the foam cannot be secured. Taking advantage of such properties, it can be suitably used as a material for sports shoes or a support for heavy objects. In addition, it effectively uses a fine and highly breathable cell structure, for example, as a spring substitute in a spring bed or sofa that requires excellent heat dissipation and impact resilience, and as a sound absorbing or sound insulating material. It can be applied.

In the high impact resilience foam according to the present invention, the above-mentioned components are weighed and preliminarily stirred by a conventionally known method to obtain a polyol component, and the isocyanate component is added to the polyol component by using an injector or a stirrer. It is produced by rapidly stirring and mixing, and then quickly putting it in and out of the required molding die. Further, manufacturing by slab molding or the like is also possible.

[0029]

[Experimental Example] An experimental example of the high impact resilience foam according to the present invention will be described below. This high impact resilience foam is basically obtained by adding a polyol having a molecular weight of 6000 or more, MDI and a crosslinking agent having a functional group of 3 or more, a catalyst and additives such as water as a foaming agent in predetermined ratios shown in the following tables. After being mixed in, and foamed and cured by free rise foaming, cut processing is performed to obtain a test piece that meets the test described below. For each of the obtained Examples and Comparative Examples,
Reactivity when obtaining each test piece (good: ○, problem: △,
Bad: ×), density (kg / m ³ ) and impact resilience (%) were observed and measured, respectively, and finally the overall evaluation as the high impact resilience foam according to the present invention was good (○), bad ( It was expressed by x). The respective raw materials used in the production of the respective test pieces in this experimental example are described below. In addition, the numbers for the raw material compositions in each table are set to 100 parts by weight for all polyols and are shown as parts by weight.

(Basic materials used) Polyol A (molecular weight 3000): trade name GL-300
0; Sanyo Kasei Co., Ltd., Polyol B (molecular weight 5000): Trade name FA-70
3; Sanyo Kasei Co., Ltd. Polyol C (molecular weight 6000): trade name PML-70
01K; Asahi Glass Polyol D (Molecular weight 10,000): Trade name PML-7
012; Asahi Glass Sub-Polyol (Molecular Weight 6000): Trade Name POP3
4-28; Mitsui Takeda Chemical Co., Ltd./MDI: trade name Millionate MTL; Nippon Polyurethane Industry Co., Ltd./TDI: trade name T-80; Nippon Polyurethane Industry Co., Ltd./crosslinking agent A: general-purpose diethanolamine; Mitsui Chemicals Co., Ltd./crosslinking agent B: General-purpose ethylene glycol; manufactured by Mitsui Chemicals; catalyst A: trade name Me-DABCO; manufactured by Mitsui Air Products; catalyst B: trade name NIAX A-1; manufactured by OSi Specialties

(Measurement Method) Density: Calculated from the obtained volume and weight of each test body. -Rebound resilience: evaluated according to JIS K 6400 (test method for flexible urethane foam). A piece of 100 × 100 × 50 mm was cut out from each of the obtained test pieces,
Evaluate with a impact resilience measuring machine.

(Experiment 1) Regarding the molecular weight of polyol, etc., polyol C was used as Example 1-1, and Example 1-
Polyol D was used as 2, Polyol D and a sub-polyol were mixed as Example 1-3, Polyol A was used as Comparative Example 1-1, and Polyol B was used as Comparative Example 1-2. . Further, for all of the examples and comparative examples in Experiment 1, MDI was used as the isocyanate, and the crosslinking agent A, catalyst A, catalyst B, water as the foaming agent and the like were used as the additives. From each composition, Examples 1-1 to 1-3 and Comparative Example 1-
Each test piece according to 1 and 1-2 was prepared, and the above-mentioned observation
The measurement was carried out. The mixing amount of each substance is shown in Table 1 below. The amount of isocyanate mixed is set so that the isocyanate index is 105.

[0033]

[Table 1]

(Results of Experiment 1) The results are also shown in Table 1 above. From this Table 1, it was confirmed that if the molecular weight of the polyol is less than 6000, the impact resilience is not sufficient even if the type and amount of the cross-linking agent and other factors are sufficient (Comparative Example 1-1 and 1-2). It was also confirmed that when the sub-polyol was mixed, the density was further improved as compared with the case where the sub-polyol was not mixed (Examples 1-2 and 1-
3).

(Experiment 2) Regarding the type and amount of the crosslinking agent, the crosslinking agent A was used as Examples 2-1 to 2-3 and Comparative Example 2-1, and the crosslinking agent B was used as Comparative Examples 2-2 and 2-3.
Was used as Comparative Example 2-4 and no crosslinking agent was added. Further, for all of the examples and comparative examples in Experiment 2, polyol C having a molecular weight of 6000 was used as the polyol, MDI was used as the isocyanate, and catalyst A, catalyst B, water as the blowing agent and the like were used as the additives. And from each composition, Examples 2-1 to 2
-3 and each of the test pieces according to Comparative Examples 2-1 to 2-4 were prepared, and the above-described observation and measurement were performed. The mixing amount of each substance is
The results are shown in Table 2 below. The amount of isocyanate mixed is set so that the isocyanate index is 105. In addition, as an example of the cross-linking agent A, Example 1-1 according to Experiment 1 is also shown.

[0036]

[Table 2]

(Results of Experiment 2) The results are also shown in Table 2 above. From Table 2, the case without the cross-linking agent, the cross-linking agent B,
That is, when a bifunctional crosslinking agent was used, it was confirmed that the impact resilience was not sufficient even if other elements were sufficient (Comparative Examples 2-2 to 2-4). Even when the cross-linking agent A is used, the addition amount is 0.1 to 1 with respect to the total amount of polyol based on 100 parts by weight.
It was confirmed that a sufficient impact resilience could not be obtained unless the content was within the range of 5 parts by weight (Examples 1-1 and 2-3 and Comparative example 2-1).

(Experiment 3) Regarding the Addition Amount of Water as a Foaming Agent Examples 3-1 to 3-3 and Comparative Examples 3-1 and 3-2
On the other hand, those with different amounts of water added as the foaming agent were used. Further, for all of the Examples and Comparative Examples in Experiment 3, the polyol D and the sub-polyol expected to have the highest impact resilience were used as the polyol, MDI was used as the isocyanate, and the crosslinking agent A, the catalyst A and the catalyst were used as the additives. B was used. And from each composition, each test piece which concerns on Examples 3-1 to 3-3 and Comparative Examples 3-1 and 3-2 was produced, and the above-mentioned observation and measurement were carried out. The mixing amount of each substance is shown in Table 3 below. The amount of isocyanate mixed is set so that the isocyanate index is 105.

[0039]

[Table 3]

(Results of Experiment 3) The results are also shown in Table 3 above. From Table 3, as the amount of water added as a foaming agent increases, the impact resilience decreases, and when the amount exceeds about 1 part by weight (Comparative Example 3-1) per 100 parts by weight of all polyols, it is defined in the present invention. It was confirmed that the impact resilience was less than 65%.

(Experiment 4) MD in all isocyanates
MDI and TDI as isocyanates for the mixing proportions of I are given in Table 4 below.
The test pieces according to Examples 4-1 to 4-3 and Comparative Examples 4-1 and 4-2 were prepared by using the mixture as described in 1. and the mixing ratio. Further, in all of the Examples and Comparative Examples in Experiment 4, as the polyol, the polyol D and the sub-polyol, which can be expected to have the highest impact resilience, were used, and as the additives, the crosslinking agent A, the catalyst A, the catalyst B, and the foaming agent were used. Water and the like were used. The amount of isocyanate mixed is set so that the isocyanate index is 105. In addition, as an example in which the MDI was 100%, Example 3-1 according to Experiment 3 was also described.

[0042]

[Table 4]

(Results of Experiment 4) The results are shown in Table 4 above. From this Table 4, it was confirmed that the high impact resilience foam according to the present invention can be produced by mixing at least 40 parts by weight of MDI as the isocyanate. Basically, the density and the impact resilience of the obtained high impact resilience foam are changed so as to be changed by the change of MDI: TDI.

[0044]

As described above, according to the high impact resilience foam of the present invention, diphenylmethane diisocyanate (MDI) capable of attaining the improvement of the density is used and the impact resilience is improved by the molecular weight of 6000 or more. By using a polyol having ## STR3 ## and a predetermined amount of a cross-linking agent having three or more functional groups, a physical property value of 65% or more in impact resilience is achieved at a density of 70 kg / m ³ or more, On the other hand, a foam capable of achieving high impact resilience was obtained without causing a bottoming phenomenon.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideo Suzuki             Stock No.5, 380, Horiyamashita, Hadano City, Kanagawa Prefecture             Inoac Technical Research Institute F-term (reference) 4J034 BA03 DA01 DB04 DB05 DB07                       DC50 DG02 DQ00 HA01 HA11                       HA14 HC12 HC64 HC71 KA01                       KD01 KD04 KD12 KE02 NA03                       QA05 QC01 RA03 RA10

Claims (4)

[Claims] 1. A high impact resilience foam comprising a polyurethane resin obtained by mixing at least one polyol, isocyanate and various additives, wherein a substance having a molecular weight of 6000 or more is used as the polyol, and diphenylmethane diisocyanate (isocyanate is used as the isocyanate. MDI) is used as a cross-linking agent, which is one of the additives, and a substance having 3 or more functional groups is added to 100 parts by weight of all polyols.
A high impact resilience foam characterized by having a density of 70 kg / m ³ or more and a impact resilience of 65% or more by adding 0.1 to 15 parts by weight, preferably 1 to 15 parts by weight. 2. The unsaturated degree of the polyol is 0.07.
The high impact resilience foam according to claim 1, which is set to not more than mmol / g. 3. The high impact resilience foam according to claim 1, wherein a graft polyol is used as one of the polyols. 4. The diphenylmethane diisocyanate
(MDI) is based on 100 parts by weight of total isocyanate,
The high impact resilience foam according to any one of claims 1 to 3, which is mixed in a proportion of at least 40 parts by weight or more.