JPH04366119A - Production of flexible polyurethane foam - Google Patents

Abstract

PURPOSE:To produce the title foam with a reduced hardness using water as the sole blowing agent without using any halocarbon blowing agent. CONSTITUTION:The title compsn. is produced by reacting a polyisocyanate component with a polyol component in the presence of a filler consisting of an unfoamed polyurethane resin powder together with water as the sole blowing agent.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for producing flexible polyurethane foam. Specifically, by using a specific filler, only water is used as a blowing agent without using halocarbons together. Even in such a case, the present invention relates to a method for producing a flexible polyurethane foam having characteristics of reduced hardness.

0002

BACKGROUND OF THE INVENTION Flexible polyurethane foams are widely used in various applications including automobile parts and furniture. As is well known, polyurethane foam is generally produced by reacting polyisocyanate raw materials and polyol raw materials in the presence of a blowing agent containing water, and various polyurethane foams such as flexible grades are produced depending on the types of polyisocyanate raw materials and polyol raw materials. can get.

In the above reaction, foaming is achieved by carbon dioxide gas generated by the reaction between polyisocyanate and water, but in actual reactions, in order to improve the performance of the resulting foam, chlorofluorocarbons and Halocarbons are used as auxiliary blowing agents. By the way, in recent years, it has been pointed out that halocarbons may cause destruction of the ozone layer, so the use of halocarbons is being regulated or abolished.

0004

[Problems to be Solved by the Invention] However, when only water is used as a blowing agent, it is necessary to increase the amount of water to some extent, and as a result, a relatively large number of urea bonds are formed, resulting in a soft Polyurethane foam is hard and has an inferior compression set, and therefore has disadvantages in that it is uncomfortable to sit on as a cushioning material and does not have sufficient durability. An object of the present invention is to provide a method for producing a flexible polyurethane foam that has particularly low hardness even when only water is used as a blowing agent without the use of halocarbons.

[0005]

[Means for Solving the Problem] As a result of extensive studies in view of the above circumstances, the present inventors have found that the above object can be easily achieved by using a specific filler, and the present invention has been made. has been completed. That is, the gist of the present invention is to use a non-foamed polyurethane resin powder as a filler when producing a flexible polyurethane foam by reacting a polyisocyanate raw material and a polyol raw material in the presence of water as a blowing agent. A method for producing a flexible polyurethane foam is provided.

The present invention will be explained in detail below. The polyisocyanate raw material used in the present invention is, for example, an organic compound in which two or more NCO groups are bonded into the same molecule, and specific examples thereof include toluene diisocyanate, crude toluene diisocyanate, 4,4'-diphenylmethane Examples include diisocyanates, polymethylene polyphenylisocyanates, and polyisocyanates partially modified by urethanization, trimerization, carbodiimidization, or amidation. Two or more of these may be used in combination. In the present invention, particularly suitable polyisocyanate raw materials include toluene diisocyanate,
Crude toluene diisocyanate, etc.

The polyol raw material used in the present invention is typically a polyether polyol obtained by adding an alkylene oxide to an initiator. Examples of initiators include glycols such as ethylene glycol and propylene glycol, triols such as glycerin and trimethylolpropane, polyfunctional hydroxyl group-containing compounds such as pentaerythritol, sorbitol, and sucrose, diethanolamine, and triethanol. Amines and the like are used, and examples of alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, and mixtures thereof. In the present invention, a particularly suitable polyol raw material has a functional group number of 2 to 8, preferably 3 to 5, and an average equivalent number of 600.
-2000, preferably 700-1500 polyether polyol.

[0008] The ratio of polyisocyanate raw material and polyol raw material used is 0.5 to 1 as NCO/OH equivalent ratio.
．． The amount of water as a blowing agent is usually 1 to 10 parts by weight, preferably 2 to 6 parts by weight, per 100 parts by weight of the polyol raw material.

A feature of the present invention is that a non-foamed polyurethane resin powder is used as the filler. Here, the polyurethane resin includes, in addition to polyurethane, polyurea and polyurea polyurethane obtained by the reaction of polyisocyanate and polyamine. In the present invention, the polyurethane resin particularly preferably used is produced by reaction injection molding (RIM). In other words, RIM introduces polyisocyanate, polyol, polyamine, etc. under pressure into a mixing chamber, causes them to collide violently, and causes them to protrude into a closed mold.The reaction is completed within the mold in a short period of time to form a polyurethane resin molded product. It is a manufacturing technology. In particular, RIM molded products are used in large quantities for parts such as automobile fascias, fenders, and bumpers. Therefore, the effective use of RIM molded products recovered from used cars is considered an important social issue from the perspective of resource utilization. Of course, burrs and scraps collected during the RIM process can also be suitably used.

[0010] In RIM, 4,4'-diphenylmethane diisocyanate and its prepolymers are usually preferably used as the polyisocyanate. The polyol has a functional group number of 2 to 3 and an average equivalent number of 1.
500 to 2000 polyether polyols are used, and as polyamines terminally aminated polyethers derived from the polyether polyols mentioned above are used. Further, as the crosslinking agent or chain extender, ethylene glycol, diethyltoluenediamine (DETDA), etc. are used.

[0011] In the present invention, the filler usually contains 300
Particles having a particle size of .mu.m or less, preferably 200 .mu.m or less are used. The amount used is not particularly limited, but is usually selected appropriately from a range of 100 parts by weight or less per 100 parts by weight of the polyol raw material, but it can produce a flexible polyurethane foam that maintains low hardness characteristics. For this purpose, the amount is preferably in the range of 5 to 50 parts by weight.

Incidentally, the addition of fillers has been conventionally carried out to improve physical properties such as strength and to increase the weight, and generally, the addition of fillers increases hardness and density. Therefore, the fact that the hardness can be lowered by adding a filler as in the present invention is an unexpected effect considering the conventional usage of fillers.

[0013] As the reaction method in the present invention, any one of a one-shot method, a prepolymer method, or a semi-prepolymer method can be adopted. As in the conventional method, water as a blowing agent is added to the polyol raw material in advance.
Fillers, optional catalysts, foam stabilizers, etc. are added.

[0014] Regarding the catalyst and foam stabilizer, there are no restrictions on the type and amount used, and they can be determined in the same manner as in conventionally known methods. Examples of catalysts include amine compounds such as triethylenediamine, tetramethylhexamethylenediamine, and dimethylcyclohexylamine; organic tin compounds such as stannath octate and dibutyltin dilaurate; and examples of foam stabilizers include:
Examples include various siloxanes and polyalkylene oxide block copolymers.

In the present invention, in addition to the above-mentioned catalyst and foam stabilizer, trischloroethyl phosphate, trischloroethyl phosphate,
Appropriate amounts of flame retardants such as trisdichloropropyl phosphate and chlorinated paraffin, pigments such as carbon black and titanium oxide, and stabilizers such as di-t-butylphenol and α-methylstyrene may be added to the polyol raw material.

[0016]

[Examples] The present invention will be explained in more detail with reference to Examples and Comparative Examples.
The present invention is not limited to the following examples. The reaction components used in the following examples are as follows, and the method for measuring the physical properties of the obtained flexible foam is as follows.

<Polyisocyanate raw material> TDI-80
(2,4TDI: 80%, 2,6TDI: 20%) <Polyol raw material> Polyether polyol with number of functional groups 3 and average number of equivalents 1000 <Filler>4,4'-diphenylmethane diisocyanate and number of functional groups 3 and average number of equivalents 1666 (Molecular weight 500
0) polyether polyol (containing 10% glass fiber) and DETDA as main raw materials.
00μm) <Additives> Urethane catalyst: Amine foam stabilizer: Silicone surfactant

4. Physical property measurement method Core density (Kg/m3): ASTM
25% according to D-1564 Hardness (Kg/314cm2): JI
Growth rate (%) according to SK-6401: JIS
Based on K-6301 Tensile strength (Kg/cm2): JIS
Tear strength (Kg/cm) according to K-6301: JIS K
-Resilient modulus (%) according to 6301: JIS
50% according to K-6401 Humid heat compression set rate (%): JIS K-6
50% according to 401 Dry heat compression set rate (%): JIS K-6
Air permeability (c.f.m.): Measured with Amsco air flow meter

Examples 1 to 3 and Comparative Example 1 Flexible urethane foams were produced according to the formulations shown in Table 1 in the following manner. All other components except the polyisocyanate raw material were weighed and added to the polyol raw material, and after stirring for 10 seconds under the condition of 3000 rotations, the polyisocyanate raw material was weighed and added, and after stirring for 3 seconds under the same conditions, It was poured into a temperature-controlled aluminum mold (35 x 35 x 7 cm). Next, after curing at 80° C. for 6 minutes, the mold was demolded and immediately crushed. After storing the obtained foam for two days according to JIS standards, physical properties were measured, and the results are shown in Table 1.

[0020]

[Table 1]
Comparative example 1 Example 1 Example 2
Example 3────────────────────
────────────────── [Blend] Polyol
100 100
100 100 filler
0
10 20
30 water
3.2 3.
2 3.2 3.2
Urethane catalyst 0.
21 0.21 0.2
1 0.21 Foam stabilizer
1.1
1.1 1.1
1.1TDI-80 (Index)
100 10
0 100 100
[Physical properties]

Core density (Kg/
m3) 42.2
45.0 49.0
50.225% Hardness (Kg/314cm2)
17.8 17.2
14.5 13.3 Growth rate (%)
147 184
151 141 Tensile strength (Kg/
cm2) 1.01
1.79 1.56
0.98 tear strength (Kg/cm)
1.03 0.93
0.75 0.86 Resilience modulus (%) 55
48 53
4550% Dry heat compression set rate (%)
4.9 5.6
6.3 6.550%
Humid heat compression set rate (%) 7.5
7.9 8.5
10.9 Breathability (c.f.m)
1.72 0.7
1 1.82 0.67
──────────────────────────
────────────

Examples 4 to 6 and Comparative Example 2 Foams were produced in the same manner as in Example 1, except that the formulation was changed to the one shown in Table 2, and the physical properties were measured. The results of physical property measurements are shown in Table-2.

[0022]

[Table 2]
Comparative example 2 Example 4 Example 5
Example 6────────────────────
────────────────── [Composition]


polyol
100 100
100 100 filler
0 10
20 30 water
5.5
5.5 5.5
5.5 Urethane catalyst
0.3 0.3
0.3 0.3 Foam stabilizer
1
．． 2 1.2 1.
2 1.2TDI-80 (Index
) 100
100 100
100 [Physical properties]

Core density (Kg/m3) 2
6.5 27.7 28
．． 2 30.925% Hardness (Kg/
314cm2) 14.7
14.4 12.1
11.7 Growth rate (%)
124 127
136 132 Tensile strength (Kg/cm2) 1
．． 05 1.11 0.
92 0.95 tear strength (Kg/c
m) 0.67
0.62 0.58 0
．． 52 Resilience modulus (%)
51 50
53 5350% Dry heat compression set rate (%) 8.9
6.7 7.8
6.850% Humid heat compression set rate (%)
18.4 12.8
11.8 12.3 Breathability (c.f.
m) 4.13
2.47 2.86
1.68──────────────────
────────────────────

Comparative Examples 3 and 4 Foams were produced in the same manner as in Example 4, except that calcium carbonate powder and barium sulfate powder were used as fillers in varying amounts in the formulation shown in Table 2. 25% hardness (Kg/314cm2
) were measured. The obtained results are shown in FIG. 1 together with the results of Examples 4 to 6 listed in Table 2. In Figure 1, the horizontal axis is
The weight part of each filler used per 100 parts by weight of polyol, the vertical axis is 25% hardness (Kg/314cm2)
represents. And (a) is the filler in the present invention, (
b) is the result of using calcium carbonate powder, and (c) is the result of using barium sulfate powder.

[0024]

Effects of the Invention According to the manufacturing method of the present invention as explained above, by using a polyurethane-based reaction injection molded powder as a filler, only water can be used as a blowing agent without using halocarbons together. Even when used, a flexible polyurethane foam that maintains low hardness properties can be obtained. Further, as the filler mentioned above, it is possible to use burrs collected in the reaction injection molding process, scraps generated, etc., so that it can also meet the social need of recycling resources. Therefore, the present invention is compatible with the stricter regulations on the use of halocarbons, and has great industrial value.

[Brief explanation of the drawing]

FIG. 1 shows the change in 25% hardness (Kg/314 cm2) of flexible polyurethane foam depending on the type of filler. (a) is the result of using the filler in the present invention, (b) is the result of using calcium carbonate powder, and (c) is the result of using barium sulfate powder.

Claims (1)

[Claims] [Claim 1] In manufacturing a flexible polyurethane foam by reacting a polyisocyanate raw material and a polyol raw material in the presence of water as a blowing agent, a powder of a non-foamed polyurethane resin is used as a filler. A method for producing flexible polyurethane foam.