JP4948055B2 - Polyurethane foam and method for producing the same - Google Patents

Description

  The present invention relates to a polyurethane foam obtained by foaming foamable beads in a polyurethane foam raw material during a foaming reaction between a polyol and a polyisocyanate, and a method for producing the same.

  Conventionally, as a method for producing a lightweight polyurethane foam, an unexpanded expandable bead is added to a polyurethane foam raw material, and the expandable bead is foamed by a foaming reaction between a polyol and a polyisocyanate. A method of dispersing in the foam has been proposed.

  However, in the conventional production method using expandable beads, expandable beads once expanded during the foaming reaction of polyol and polyisocyanate may collapse and shrink, and a good polyurethane foam may not be obtained. . The inventor presumes that this is because the exothermic temperature becomes too high during the foaming reaction of the polyol and the polyisocyanate.

JP-A-48-77957

  The present invention has been made in view of the above points, and an object of the present invention is to obtain a lightweight polyurethane foam by preventing the expandable beads from being foamed and then collapsing and shrinking.

The invention according to claim 1 is an unfoamed polyurethane foam in which a polyol and a polyisocyanate are foamed and reacted with 3 to 5 parts by weight of a foaming agent and a heat-resistant temperature of 80 to 150 ° C. It is characterized by comprising 5 to 30 parts by weight of expandable beads and 10 to 30 parts by weight of inorganic hydrate for foaming reaction, and having a CI value of 3.5 to 5.5.

According to a second aspect of the present invention, there is provided a process for producing a polyurethane foam by subjecting a polyol and a polyisocyanate to a foaming reaction at room temperature and atmospheric pressure to obtain a polyurethane foam. 5-30 parts by weight of unfoamed expandable beads having a heat-resistant temperature of 80-150 ° C. and 10-30 parts by weight of inorganic hydrate are added, and the expandable beads are added during the foaming reaction with the polyol and polyisocyanate. It is made to foam.

  According to the polyurethane foam of the invention of claim 1, 10 to 30 parts by weight of the inorganic hydrate per 100 parts by weight of the polyol is heated by the foaming reaction heat of the polyol and polyisocyanate to release moisture. In addition, the heat of foaming reaction can be suppressed by the latent heat of vaporization of water, and the foamed beads once foamed can be prevented from collapsing due to heat and shrinking, resulting in a lightweight polyurethane foam having a good foamed state. In addition, since the foamable beads sufficiently foamed by the heat of foaming reaction are dispersed in the polyurethane foam, the CI value (Comfort Index) can be increased to 3.5 to 5.5, and it is seated when used as a cushion body. Thus, a polyurethane foam having a small feeling of bottoming can be obtained.

  The CI value (Comfort Index) is a value calculated by [CI value = 65% compression hardness of specimen / 25% compression hardness of specimen]. The CI value of 65% compression means that the displacement amount (compression displacement amount) due to compression is 65% with respect to the original thickness of 100%, in other words, the thickness after compression with respect to the original thickness of 100%. The compression state is 35%, which is the same as the compression rate of 65%. The 25% compression means that the displacement amount (compression displacement amount) due to compression is 25% with respect to the original thickness of 100%. In other words, the thickness after compression is 75% with respect to the original thickness of 100%. The compressed state is the same as the compression rate of 25%. The larger the CI value, the softer the feeling at the initial stage of compression and the lower the feeling of bottoming.

According to the manufacturing method of the invention of claim 2, the inorganic hydrate contained in 10 to 30 parts by weight with respect to 100 parts by weight of polyol releases moisture by being heated by the heat of foaming reaction of polyol and polyisocyanate. The heat of the evaporating reaction can be suppressed by the latent heat of vaporization of water, and the foamed beads once foamed can be prevented from collapsing due to heat and shrinking, and a lightweight polyurethane foam having a good foamed state can be obtained. . Moreover, the foamed beads sufficiently foamed by the foaming reaction heat are dispersed in the polyurethane foam, so the CI value can be increased, and when used as a cushion body, the polyurethane foam has a low bottoming feeling when seated. You can get a body.

  As the polyol used in the present invention, any one or both of known ether polyols and ester polyols used for flexible polyurethane foams are used.

  Examples of ether polyols include polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sucrose, or polyhydric alcohols thereof. The polyether polyol which added alkylene oxides, such as ethylene oxide and a propylene oxide, can be mentioned. As ester polyols, polycondensation of aliphatic carboxylic acids such as malonic acid, succinic acid and adipic acid and aromatic carboxylic acids such as phthalic acid and aliphatic glycols such as ethylene glycol, diethylene glycol and propylene glycol. The polyester polyol obtained in this way can be mentioned.

  The polyisocyanate may be aromatic, alicyclic or aliphatic, and may be a bifunctional isocyanate having two isocyanate groups in one molecule, or three in one molecule. Trifunctional or higher isocyanates having the above isocyanate groups may be used, and these may be used alone or in combination.

  For example, as the bifunctional isocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'- Fragrances such as diphenylmethane diate, 2,2'-diphenylmethane diisocyanate, xylylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisonate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate Aliphatic ones such as cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, methylcyclohexane diisocyanate, butane-1,4-diisocyanate Over DOO, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, there may be mentioned aliphatic, such as lysine isocyanate.

  Examples of the tri- or higher functional isocyanate include 1-methylbenzole-2,4,6-triisocyanate, 1,3,5-trimethylbenzole-2,4,6-triisocyanate, biphenyl-2,4,4 ′. -Triisocyanate, diphenylmethane-2,4,4'-triisocyanate, methyldiphenylmethane-4,6,4'-triisocyanate, 4,4'-dimethyldiphenylmethane-2,2 ', 5,5' tetraisocyanate, triisocyanate Examples thereof include phenylmethane-4,4 ′, 4 ″ -triisocyanate, polymeric MDI, and the like. Other urethane prepolymers can also be used. The polyisocyanate is not limited to one type, but one type. For example, one type of aliphatic isocyanate and The two types of aromatic isocyanates may be used in combination.

  Water is added as a blowing agent for the polyol and polyisocyanate. The amount of water as a blowing agent is preferably 3 to 5 parts by weight with respect to 100 parts by weight of polyol. When the amount is less than 3 parts by weight, the exothermic temperature at the time of the foaming reaction between the polyol and the polyisocyanate is not sufficiently increased. As a result, the foamable beads are not sufficiently foamed and a good polyurethane foam cannot be obtained. On the other hand, if it is more than 5 parts by weight, the exothermic temperature during the foaming reaction between the polyol and polyisocyanate will increase too much, and the polyurethane foam will not foam well, but will also collapse after the foaming beads once foamed. As a result, the polyurethane foam shrinks, and a good polyurethane foam cannot be obtained.

  As the expandable beads, unexpanded beads are used together with the polyol and polyisocyanate. The unfoamed expandable beads are preferable because they have a particle size smaller than that of the foamed beads after foaming, and a desired amount can be dispersed and mixed in the polyurethane raw material. In general, in the method of manufacturing a molded article of beads, unexpanded expandable beads are primarily expanded, and the expanded particles are expanded in a spherical state up to a particle size of 1 to 5 mm. It is made into a molded body by being put in and heated and fused. However, in the present invention, the primary foamed beads are mixed and dispersed in the polyurethane raw material to obtain the polyurethane foam of the present invention because the particle size of the foamable beads is too large and the desired amount cannot be mixed and dispersed. It is not preferable.

  Examples of the foamable bead material include polycarbonate, methyl methacrylate, polyethylene / polypropylene copolymer, polyethylene / polystyrene copolymer, acrylic / styrene copolymer, and polyuric acid. Among these, as a preferable example of the expandable beads, expandable polystyrene beads can be exemplified. The expandable polystyrene beads are made by impregnating polystyrene or styrene-based copolymer plastic with a foaming agent. As the foaming agent used for the expandable polystyrene beads, pentane, butane, propane or the like, and a polymer having a number average molecular weight of 1000 to 3000 is preferable. The unfoamed expandable beads are more preferably those having a heat resistant temperature of 80 to 150 ° C. When the temperature is lower than 80 ° C., the expandable beads are once foamed and then collapse and easily contract. On the other hand, when the temperature is higher than 150 ° C., the expandable beads do not foam. The particle size of the expandable beads is preferably about 0.3 to 1.6 mm. Further, the addition amount of the expandable beads is preferably 5 to 30 parts by weight with respect to 100 parts by weight of the polyol. When the amount is less than 5 parts by weight, it is difficult to obtain the light weight and hardness increase effect of the polyurethane foam. On the other hand, when it exceeds 30 parts by weight, the foaming balance is lost during the foaming reaction of polyol and polyisocyanate, making it difficult to obtain a polyurethane foam.

  Inorganic hydrate refers to a compound that releases moisture by heating with the heat of foaming reaction of polyol and polyisocyanate and can suppress the heat of foaming reaction by the latent heat of vaporization of water. Specific examples include at least one selected from the group consisting of dihydrate gypsum, magnesium sulfate hydrate, and magnesium phosphate hydrate. The amount of the inorganic hydrate added is preferably 10 to 30 parts by weight with respect to 100 parts by weight of the polyol. When the amount is less than 10 parts by weight, it is difficult to obtain the effect of suppressing the foaming reaction heat. On the other hand, when the amount exceeds 30 parts by weight, the foaming balance is lost during the foaming reaction between the polyol and the polyisocyanate, making it difficult to obtain a polyurethane foam.

  Examples of other additives include foam stabilizers and pigments. Any foam stabilizer may be used as long as it is used for a flexible polyurethane foam. Examples thereof include silicone foam stabilizers, fluorine-containing compound foam stabilizers, and known surfactants. As the pigment, those according to the required color are used.

  A catalyst is used for the reaction between the polyol and the polyisocyanate. As the catalyst, those known for flexible polyurethane foams can be used. For example, amine catalysts such as triethylamine, triethylenediamine, diethanolamine, dimethylaminomorpholine, N-ethylmorpholine, tetramethylguanidine, tin catalysts such as stannous octoate and dibutyltin dilaurate, phenylmercurypropionate or lead octenoate And metal catalysts (also referred to as organometallic catalysts). The general amount of the catalyst is about 0.01 to 2.0 parts by weight with respect to 100 parts by weight of the polyol.

  Production of the polyurethane foam in the present invention is carried out by known slab foaming in which a polyol and a polyisocyanate are subjected to a foaming reaction at room temperature and atmospheric pressure. Specifically, the polyurethane foam raw material (reaction mixed raw material) composed of the polyol, polyisocyanate, unfoamed expandable beads, catalyst, water, inorganic hydrate and other appropriate additives is discharged onto a belt conveyor, While the belt conveyor moves, the polyurethane foam raw material is naturally foamed under normal temperature and atmospheric pressure, and is continuously produced by curing. At that time, the polyurethane foam raw material may be reacted by any one of the one-shot method and the prepolymer method. The one-shot method is a reaction method in which polyol and polyisocyanate are directly reacted in the presence of unfoamed expandable beads, catalyst, water, inorganic hydrate, and other appropriate additives. On the other hand, in the prepolymer method, a polyol and polyisocyanate are reacted in advance to obtain a prepolymer having an isocyanate group at the terminal, and unexpanded expandable beads, catalyst, water, inorganic hydrate and addition to the prepolymer In this method, a polyol is reacted in the presence of an agent or the like.

  Examples of the present invention will be specifically described below together with comparative examples. Each component shown in Table 1 and Table 2 was blended according to the blending ratio in the same table, and subjected to foaming reaction by slab foaming using a one-shot method, to obtain a polyurethane foam. Examples 1 to 4 are examples in which inorganic hydrate 1 was used and the amount of expandable beads was changed, and Example 5 was an example in which inorganic hydrate 2 was added instead of inorganic hydrate 1. On the other hand, Comparative Example 1 is an example in which the addition amount of inorganic hydrate 1 is reduced, Comparative Example 2 is an example in which the addition amount of foaming agent (water) is increased, and Comparative Example 3 is an addition amount of foaming agent (water) is reduced. Example 4 and Comparative Example 4 are examples in which no expandable beads were added.

  The polyols in Tables 1 and 2 are polyether polyols (product number: GP3050F, functional group number f = 3, OH number = 56, Mw = 3000, manufactured by Sanyo Chemical Industries, Ltd.), inorganic hydrate 1 is dihydrate gypsum, inorganic Hydrate 2 is magnesium phosphate octahydrate, amine catalyst is N, N, N ', N ", N" -pentamethyldiethylenetriamine (product number: Kao Riser No3, manufactured by Kao Corporation), metal catalyst is octylic acid Stannous (product number: MRH110, manufactured by Johoku Chemical Co., Ltd.), foam stabilizer is silicone foam stabilizer (product number: BF2370, manufactured by Goldschmidt), expandable beads are expandable polystyrene beads (product number: SSBTX17, heat resistance temperature 120) -130 ° C, particle size 0.7-0.9 mm, manufactured by Hitachi Chemical Co., Ltd., polyisocyanate is tolylene diisocyanate (product number: T-8) , Which is manufactured by Nippon Polyurethane Industry Co., Ltd.). In addition, when a foaming state was observed visually, about Examples 1-5 and Comparative Example 4, it was a favorable foaming state. On the other hand, in Comparative Example 1, the amount of inorganic hydrate 1 added was small, and a good foam was not obtained. In Comparative Example 2, since the amount of the foaming agent (water) added was large, the foaming reaction became intense, causing shrinkage after foaming, and no foam was obtained. In Comparative Example 3, since the addition amount of the foaming agent (water) was small, only an unfoamed foam that was not foamed sufficiently and foamable beads were not foamed was obtained.

  Further, when foaming the polyurethane foams in Examples and Comparative Examples, a thermocouple was inserted into the foamed bodies, and the maximum heat generation temperature was measured with an electronic measuring instrument (product number: NR-1000, manufactured by Keyence Corporation). Furthermore, for the polyurethane foams of Examples and Comparative Example 4, the density was measured according to JIS K7222-2004, the 25% compression hardness was measured according to JIS K6400-2: 2004 D method, and the CI value Therefore, 25% ILD (200φ) and 65% ILD (200φ) were measured according to JIS K 6400-2: 2004 D method. The 25% compression hardness is indicated by a compressive stress when the sample size is 50 × 150 × 100 mm and the sample is completely compressed to 25%. 25% ILD (200φ) is the hardness when a polyurethane foam is compressed 25% using a 200 mm diameter pressing plate, while 65% ILD (200 φ) is a polyurethane foam using a 200 mm diameter pressing plate. It is the hardness when the body is compressed by 65%, and the CI value is calculated by [65% ILD / 25% ILD]. Moreover, since the favorable polyurethane foam was not obtained about Comparative Examples 1-3, a density, 25% compression hardness, 25% ILD (200 (phi)), and 65% ILD (200 (phi)) were not able to be measured. The measurement results are as shown in the lower part of Tables 1 and 2.

As understood from the measurement results in Table 1, in Examples 1 to 5, it can be seen that the foamed state of the polyurethane foam is good. Moreover, as understood from the measurement results of Tables 1 and 2, the polyurethane foams of Examples 1 to 5 were compared to the polyurethane foam of Comparative Example 4 in which no foamable beads were added, relative to the density. The 25% compression hardness was high. From this, it can be seen that the polyurethane foams of Examples 1 to 5 have a good foamed state and are high in lightness and hardness. Further, the polyurethane foams of Examples 1 to 5 have a CI value of 3.8 to 5.2, which is 2 to 3 times as large as the CI value of Comparative Example 4 of 1.7. It is understood that when used as a cushion body, it is good with little bottoming. ,

Claims (2)

In a polyurethane foam obtained by foaming reaction of a polyol and a polyisocyanate,
3 to 5 parts by weight of a foaming agent, 5 to 30 parts by weight of unfoamed expandable beads having a heat resistant temperature of 80 to 150 ° C., and 10 to 30 parts by weight of inorganic hydrate are added to 100 parts by weight of the polyol. And a polyurethane foam characterized by having a CI value of 3.5 to 5.5. In the method for producing a polyurethane foam, a polyurethane foam is obtained by subjecting a polyol and a polyisocyanate to a foaming reaction at normal temperature and atmospheric pressure.
3 to 5 parts by weight of a foaming agent, 5 to 30 parts by weight of unfoamed expandable beads having a heat resistant temperature of 80 to 150 ° C., and 10 to 30 parts by weight of inorganic hydrate are added to 100 parts by weight of the polyol. And
A method for producing a polyurethane foam, wherein the foamable beads are foamed during a foaming reaction with the polyol and polyisocyanate.