JP5005215B2 - Polyurethane foam - Google Patents

Description

  The present invention relates to a polyurethane foam that is used as, for example, bedding, a sound absorbing material, a cushioning material, and the like, and is excellent in strain characteristics represented by compression residual strain.

Conventionally, when producing a low-density flexible polyurethane foam having a density of 25 kg / m ³ or less, when only the foaming agent is water, it is necessary to increase the amount of water added, so that the foaming reaction is accelerated. Thus, the heat generation temperature during foaming reaches 170 ° C. or higher. For this reason, there is a possibility of self-ignition based on oxidative deterioration (scorch) of polyurethane, and the resulting soft polyurethane foam is discolored by the scorch. In order to avoid such a situation, a technique is known in which methylene chloride or liquefied carbon dioxide gas is added as a foaming aid with the conventional amount of water added.

However, methylene chloride is one of the substances that adversely affect the environment and its use is regulated. On the other hand, foaming with liquefied carbon dioxide requires special equipment for supplying the liquefied carbon dioxide at a high pressure. In order to perform foaming smoothly, the production conditions are limited and the production cost also increases. Therefore, a technique for adding a hydrate of an inorganic compound such as a hydrate of calcium phosphate or a hydrate of calcium sulfate for the purpose of endotherm has been proposed (see, for example, Patent Document 1). According to this technique, as the reaction temperature rises, the hydrate of the inorganic compound decomposes and water dissociates and evaporates, so the heat generated by the reaction is absorbed and the maximum exothermic temperature of the polyurethane foam is suppressed. .
International Publication WO 90/03997 (Page 2)

However, in the technique described in Patent Document 1, the obtained polyurethane foam has very large strain characteristics, that is, compression residual strain (compression permanent strain), and such polyurethane foam can withstand actual use. It was not obtained. In particular, in applications where compressive force is applied during heating, distortion due to compressive force is not restored, and the standards for that application are not satisfied, making it impossible to use. Such a defect has occurred particularly when the apparent density of the polyurethane foam obtained using only water as a foaming agent is as low as 16 to 22 kg / m ³ . This is because the balance between the resinification reaction (urethane reaction) and the foaming reaction is poor, the resinification reaction becomes too strong, or the foaming reaction becomes excessive with respect to the resinification reaction. Conceivable.

  The present invention has been made paying attention to such problems existing in the prior art, and an object of the present invention is to provide a polyurethane foam capable of improving the strain characteristics of a low-density foam. There is to do.

In order to achieve the above object, the polyurethane foam of the invention according to claim 1 is obtained by reacting a raw material of a polyurethane foam containing polyols, polyisocyanates, a foaming agent, a catalyst and a hydrate of an inorganic compound. A polyurethane foam having an apparent density of 16 to 22 kg / m ³ measured according to JIS K 7222: 1999, wherein water is used as the foaming agent in an amount of 100 masses of polyols. 5-9 parts by mass per part, a resination activity constant by titration as a catalyst of 0.22 × 10-2.0 × 10, and a ratio of foaming activity constant / resinization activity constant of 0.4 × 10 ^-1 to 3.0 × 10 containing dibutyltin dilaurate amine catalysts and metal catalysts which are ^-1, further wherein the amine catalyst the polyols per 100 parts by Is characterized in that .01～0.5 parts by mass and containing the 0.1 to 0.4 parts by weight of the metal catalyst the polyols per 100 parts by weight.

  The polyurethane foam of the invention according to claim 2 is the invention according to claim 1, wherein the polyol is a polyalkylene polyol having a polyethylene oxide unit content of 4 to 12 mol%. Is.

  The polyurethane foam of the invention according to claim 3 is the invention according to claim 1 or claim 2, wherein the hydrate of the inorganic compound is a sulfate hydrate. .

According to the present invention, the following effects can be exhibited.
In the polyurethane foam of the invention according to claim 1, by using 5 to 9 parts by mass of water as a foaming agent per 100 parts by mass of polyols, the foaming is promoted and the apparent density is as low as 16 to 22 kg / m ^3. A density polyurethane foam can be obtained. Moreover, the resination activity constant by a titration method as a catalyst is 0.22 × 10 to 2.0 × 10, and the ratio of the foaming activity constant / resinization activity constant is 0.4 × 10 ^{−1 to} 3.0 × 10. By using the amine catalyst that is ^-1 , the resinification reaction and the foaming reaction can be suppressed, and the balance of these reactions can be adjusted. Furthermore, the content of the amine catalyst is 0.01 to 0.5 parts by mass per 100 parts by mass of polyols, and the content of dibutyltin dilaurate as a metal catalyst is 0.1 to 0.4 parts by mass per 100 parts by mass of polyols. By setting to, excessive progress of the resinification reaction is suppressed, and the balance between the resinification reaction and the foaming reaction is maintained. Therefore, it is possible to improve the strain characteristics represented by the compressive residual strain for the low-density foam.

  In the polyurethane foam of the invention according to claim 2, since the polyol is a polyalkylene polyol having a polyethylene oxide unit content of 4 to 12 mol%, in addition to the effects of the invention according to claim 1, The initial resinification reaction can be assisted.

  In the polyurethane foam of the invention according to claim 3, since the hydrate of the inorganic compound is a sulfate hydrate, in addition to the effect of the invention according to claim 1 or 2, The sulfate hydrate is decomposed along the foaming process of the raw material of the polyurethane foam to produce water, and the endothermic effect can be exhibited well.

In the following, embodiments that are considered to be the best of the present invention will be described in detail.
The polyurethane foam (hereinafter also simply referred to as foam) in the present embodiment is obtained as follows. That is, it can be obtained by reacting, foaming and curing a raw material of polyurethane foam containing hydrates of polyols, polyisocyanates, foaming agent, catalyst and inorganic compound. Under the present circumstances, 5-9 mass parts is used per 100 mass parts of polyols so that the water as a foaming agent may become more than usual. The catalyst has a resination activity constant by a titration method of 0.22 × 10 to 2.0 × 10 and a ratio of foaming activity constant / resinization activity constant of 0.4 × 10 ^{−1 to} 3.0 × 10. An amine catalyst with a mild activity of ^-1 is used. Furthermore, 0.1 to 0.4 parts by mass of a metal catalyst as a catalyst is used per 100 parts by mass of polyols.

  When the raw material of the polyurethane foam reacts, a resinification reaction (urethanization reaction, addition polymerization reaction) between polyols and polyisocyanates occurs to form a polyurethane skeleton. At the same time, a foaming (foaming) reaction between the polyisocyanates and water as a foaming agent occurs, and carbon dioxide gas is generated to form a foam. Furthermore, a crosslinking (curing) reaction such as a burette reaction or an allophanate reaction between these reaction products and polyisocyanates occurs, and a crosslinked structure is formed in the foam.

An amine catalyst and a metal catalyst as a catalyst are used to promote each of the above reactions. In addition, inorganic compound hydrates exhibit a function to suppress temperature rise by decomposing latent heat of vaporization when water is evaporated by the process of polyurethane foam raw materials reacting and foaming, and then evaporating the water. To do. The polyurethane foam thus obtained is a low-density polyurethane foam having an apparent density of 16 to 22 kg / m ³ measured according to JIS K 7222: 1999.

Next, the raw materials for the polyurethane foam will be described in order.
As the polyols, polyether polyols or polyester polyols are used. Of these, polyether polyols are preferable because they are excellent in reactivity with polyisocyanates and do not hydrolyze like polyester polyols. Examples of the polyether polyol include polypropylene glycol, polytetramethylene glycol, polyether polyol made of a polymer obtained by addition polymerization of propylene oxide and ethylene oxide to a polyhydric alcohol, and modified products thereof. Examples of the polyhydric alcohol include glycerin and dipropylene glycol.

  Specific examples of polyether polyols include triols obtained by addition polymerization of propylene oxide to glycerin and addition polymerization of ethylene oxide, and diols obtained by addition polymerization of propylene oxide to dipropylene glycol and addition polymerization of ethylene oxide. . When the content of the polyethylene oxide unit is large, the hydrophilicity is higher than when the content is low, and the miscibility with highly polar molecules and polyisocyanates is improved, resulting in high reactivity. Become. The polyethylene oxide unit in the polyether polyol is preferably 4 to 12 mol%. When the content of the polyethylene oxide unit is less than 4 mol%, the resinification reaction cannot be promoted sufficiently. On the other hand, when it exceeds 12 mol%, the resinification reaction proceeds excessively, and the strain characteristics of the obtained foam tend to be lowered.

  As polyester polyols, in addition to condensation polyester polyols obtained by reacting polycarboxylic acids such as adipic acid and phthalic acid with polyols such as ethylene glycol, diethylene glycol, propylene glycol and glycerin, lactone polyester polyols and polycarbonate systems A polyol is used. These polyols can change the number of functional groups and the hydroxyl value of the hydroxyl group by adjusting the kind of raw material component, the molecular weight, the degree of condensation, and the like.

  The polyisocyanates to be reacted with the polyols are compounds having a plurality of isocyanate groups, specifically, tolylene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI). ), Triphenylmethane triisocyanate, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI), and modified products thereof. The isocyanate index (isocyanate index) of the polyisocyanates may be 100 or less or more than 100, but is usually in the range of about 90 to 130, preferably about 100 to 110. Here, the isocyanate index represents the equivalent ratio of the isocyanate groups of the polyisocyanates to the active hydrogen groups such as polyols and water as a foaming agent in percentage. Therefore, an isocyanate index exceeding 100 means that polyisocyanates are in excess of polyols and the like.

The foaming agent is for foaming a polyurethane resin to form a polyurethane foam, and water that is highly reactive in the foaming reaction and easy to handle is used. When the foaming agent is water, the content is set to 5 to 9 parts by mass per 100 parts by mass of polyols in order to make the apparent density of the polyurethane foam 16 to 22 kg / m ³ . When the water content is less than 5 parts by mass, the foaming reaction is not sufficiently performed, the apparent density of the polyurethane foam tends to exceed 22 kg / m ³ , and a low-density foam cannot be obtained. On the other hand, when it exceeds 9 parts by mass, the temperature tends to rise during foaming and curing, and it becomes difficult to lower the temperature.

Next, as the catalyst, the resination activity constant by the titration method is 0.22 × 10 to 2.0 × 10, and the ratio of the foaming activity constant / resinization activity constant is 0.4 × 10 ^{−1 to} 3. An amine catalyst and a metal catalyst that are 0 × 10 ⁻¹ are used. The resinization activity constant of the amine catalyst and the ratio of the foaming activity constant / resinization activity constant are set to the above ranges in order to suppress the resinization reaction and the foaming reaction and adjust the balance of the reactions. The resinization activity constant is desirably 0.22 × 10 to 1.0 × 10 in order to effectively suppress the resinification reaction. Further, the foaming activity constant is preferably 0.8 × 10 to 6.0 × 10, and more preferably 0.8 × 10 to 0.5 × 10.

  Here, the resination activity constant and the foaming activity constant are determined by the titration method (A.T. It is a value calculated by the Farkas method [Journal of American Chemical Society, 82, 642 (1960)]. This method will be described below.

The reaction rate of resinification reaction, foaming reaction, etc. in the production of polyurethane foam is generally represented by the following formula.
dx / dt = K (ax) ²
Where x is, for example, in the case of a resinification reaction, the concentration of the isocyanate group (mol / L), a is, for example, the initial concentration of the isocyanate group and hydroxyl group (mol / L), K is the reaction rate constant, and t is the reaction time (h). Represents.

Based on this reaction rate equation, the reaction rate constant K is calculated by experimentally measuring the relationship between (ax) and t.
On the other hand, assuming that the following equation holds for the reaction rate constant, the catalyst constant Kc is determined for each catalyst.

K = Ko + KcC
However, Ko is a reaction rate constant (L / mol · h) in the case of no catalyst, Kc is a catalyst constant (L ² / (mol) ² · h) of each catalyst, and C is a catalyst concentration (mol / L) of the reaction system. ).

In general, the catalyst constant K ₁ indicating the resinization activity constant in the resinification reaction when producing a polyurethane foam is represented by a reaction system of TDI (tolylene diisocyanate) and DEG (diethylene glycol), and the foam in the foaming reaction. The catalyst constant K ₂ indicating the activating activity constant is represented by a reaction system of TDI (tolylene diisocyanate) and H ₂ O.

Wherein when resinification activity constant K ₁ is less than 0.22 × 10 is insufficient acceleration of resinification, not obtained a good foam, 2.0 × 10 the case excess resin of beyond This is accelerated and the distortion characteristics of the resulting foam deteriorate. Moreover, when the ratio of the foaming activity constant (K ₂ ) / resinization activity constant (K ₁ ) is less than 0.4 × 10 ⁻¹ , the foaming reaction is weaker than the resinification reaction, and foaming is insufficient. If the foamed reaction exceeds 3.0 × 10 ⁻¹ , the foaming reaction proceeds excessively compared to the resinification reaction, and the distortion characteristics of the resulting foam deteriorate.

Specific examples of the amine catalyst include N-methyl-N′-hydroxyethylpiperazine (K ₁ = 0.61 × 10, K ₂ = 0.11 × 10, K ₂ / K ₁ = 1.86 × 10). ^-1 ), N-ethylmorpholine (K ₁ = 0.22 × 10, K ₂ = 0.01 × 10, K ₂ / K ₁ = 0.47 × 10 ⁻¹ ), N- (N ′, N ′ -2-dimethylaminoethyl) morpholine (K ₁ = 0.93 × 10, K ₂ = 0.08 × 10, K ₂ / K ₁ = 0.81 × 10 ⁻¹ ), aliphatic monoamine (K ₁ = 0) .75 × 10, K ₂ = 0.22 × 10, K ₂ / K ₁ = 3.00 × 10 ⁻¹ ) and the like. Examples of the metal catalyst include dibutyltin dilaurate and tin octylate (tin octoate).

  The content of the amine catalyst is preferably 0.01 to 0.5 parts by mass and more preferably 0.1 to 0.5 parts by mass per 100 parts by mass of polyols. When the content of the amine catalyst is less than 0.01 parts by mass, the resinification reaction and the foaming reaction cannot be promoted sufficiently and in a well-balanced manner. On the other hand, if it exceeds 0.5 parts by mass, the resinification reaction and the foaming reaction may be excessively promoted, or the balance between the two reactions may be impaired. Moreover, content of a metal catalyst is set to 0.1-0.4 mass part per 100 mass parts of polyols. When the content of the metal catalyst is less than 0.1 parts by mass, the resination reaction and the foaming reaction are not balanced, and foaming cannot be performed satisfactorily. On the other hand, when it exceeds 0.4 parts by mass, the resinification reaction and the foaming reaction are excessively promoted, the balance between the two reactions is deteriorated, and the strain characteristic of the foam is deteriorated.

Next, a hydrate of an inorganic compound is a material that decomposes by heating and generates water by decomposition. Specifically as a hydrate of an inorganic compound, calcium sulfate dihydrate (CaSO ₄ .2H ₂ O, dihydrate gypsum, specific gravity 2.32, decomposition temperature 128 to 163 ° C.), magnesium sulfate monohydration To 7 hydrate (MgSO ₄ .H ₂ O to MgSO ₄ .7H ₂ O, specific gravity 2.57 to 1.68, decomposition temperature 150 ° C.), iron sulfate monohydrate to pentahydrate (FeSO ₄ · H ₂ O to FeSO ₄ · 5H ₂ O, specific gravity 2.97, decomposition temperature 100 to 130 ° C.) or a mixture thereof, and other monohydrate to trihydrate (Al ₂ O ₃ · H) ₂ O to Al ₂ O ₃ .3H ₂ O, specific gravity 2.4 to 3.4, decomposition temperature 150 to 360 ° C., copper sulfate pentahydrate (CuSO ₄ .5H ₂ O, specific gravity 2.29), etc. Is used. The water of hydration contained in the hydrate of the inorganic compound is water that is stably present at room temperature as a solid crystal and is crystal water. The inorganic compound hydrate is preferably a sulfate hydrate such as calcium sulfate hydrate, magnesium sulfate hydrate, or iron sulfate hydrate. This is because the sulfate hydrate can gradually decompose at a temperature of, for example, 100 ° C. or higher along the foaming process of the raw material of the polyurethane foam to produce water, thereby exhibiting an endothermic effect.

  The specific gravity of the inorganic compound hydrate is preferably 1.5 to 4.0. If the specific gravity is less than 1.5, a predetermined mass cannot be added unless a large amount of inorganic compound hydrate (powder) is added to the polyurethane foam raw material, for example, polyol. Cannot be sufficiently mixed and stirred. And the volume of the hydrate of the inorganic compound which occupies in a polyurethane foam becomes large, and the physical property as a polyurethane foam falls. On the other hand, if the specific gravity exceeds 4.0, water of an inorganic compound that tends to settle when stored for a long time in a polyurethane foam raw material, particularly in a polyol, disperses in the reaction mixture, and lowers the heat generation temperature. The function of Japanese products is reduced. The decomposition temperature of the inorganic compound hydrate is preferably 100 to 170 ° C. When the decomposition temperature is less than 100 ° C., water generated by decomposition is generated at the initial stage of foaming and curing by the polyurethane raw material, that is, at a stage where the exothermic temperature is low. May function as a foaming agent. By the way, calcium sulfate dihydrate (dihydrate gypsum) decomposes 1.5 mol water out of 2 mol water in the molecule at 128 ° C. into free water, resulting in 0.5 hydrate calcium sulfate. It becomes a thing (half water gypsum). In addition, magnesium sulfate heptahydrate is decomposed into 6 mol of water out of 7 mol of water in the molecule at 150 ° C. to become free water, and becomes magnesium sulfate monohydrate.

  The content of the inorganic compound hydrate is preferably 20 to 40 parts by mass per 100 parts by mass of the polyols. When the content is less than 20 parts by mass, the amount of water generated by decomposition is small, and the increase in the heat generation temperature based on the reaction and foaming cannot be sufficiently suppressed. On the other hand, if the content exceeds 40 parts by mass, the foam contains a large amount of inorganic compound hydrate, and as a result, the physical properties of the foam tend to decrease, and excess water is used as a foaming agent. And the foaming reaction may proceed excessively.

  Moreover, it is preferable to contain a foam stabilizer in the raw material of a polyurethane foam. The foam stabilizer is for adjusting the size and uniformity of the foam cell by the foaming agent, and a water-soluble compound is used to suppress the foam breaking action. As such a water-soluble foam stabilizer, a silicone compound is preferable. The silicone-based compound has an excellent surface-active action, can enhance the compatibility of each component of the polyurethane foam material, stabilize the bubbles, and generate fine uniform bubbles. Examples of the silicone compound (nonionic surfactant) include an organosiloxane-polyoxyalkylene copolymer, a silicone-grease copolymer, or a mixture thereof. The content of the foam stabilizer is preferably about 0.5 to 5 parts by mass per 100 parts by mass of polyols.

  In addition to the above components, the polyurethane foam raw material may contain a cell opener, a flame retardant, a crosslinking agent, a filler, a stabilizer, an antioxidant, a plasticizer, an ultraviolet absorber, a colorant, and the like as necessary. it can.

  In the case of producing a polyurethane foam, a one-shot method in which a polyol and a polyisocyanate are directly reacted, or a prepolymer having an isocyanate group at the terminal by reacting in advance with a polyol and a polyisocyanate. Any of the prepolymer methods in which a polyol is reacted with the obtained polyol is employed. Polyurethane foam is foamed and cured in the mold by injecting the polyurethane foam raw material (reaction mixture) into the slab foam obtained by foaming and curing at room temperature and atmospheric pressure, and in the mold, and clamping the mold. It may be produced by any method of the molded foam obtained. In this case, the slab foam is preferable from the viewpoint that it can be continuously produced.

The polyurethane foam thus obtained has a low density of 16-22 kg / m ³ as defined in JIS K 7222: 1999, and its compression residual strain is 4.0-9.5% The standard is 10% or less). Further, the polyurethane foam has, for example, a hardness of 60 to 90 N, a rebound resilience of 25 to 35%, a tensile strength of 60 to 75 kPa, an elongation of 90 to 130%, and a tear strength of 3.9 to 5.4 N. It has good physical properties as a foam of / cm ² and an air flow rate of 30 to 60 L / min. Such a polyurethane foam is a soft polyurethane foam that has good cushioning properties and is lightweight. The flexible polyurethane foam generally has a restoring structure in which cells (bubbles) have a communication structure. Therefore, the flexible polyurethane foam can exhibit properties such as cushioning properties, impact absorption properties, and sound absorption properties. Polyurethane foams having such physical properties are suitably used as bedding such as beds, mattresses and pillows, sound absorbing materials, cushioning materials and the like.

Now, the operation of this embodiment will be described. The resinization activity constant by the titration method as an amine catalyst is 0.22 × 10 to 2.0 × 10, and the ratio of the foaming activity constant / resinization activity constant is 0.4. × using ¹⁰ -1 to 3.0 × ^{10 -1} compounds. Since such an amine catalyst is used, the resinification reaction is suppressed, the foaming reaction for the resinification reaction is suppressed, and the reactions proceed in a well-balanced manner. Furthermore, by setting the content of the metal catalyst to 0.1 to 0.4 parts by mass per 100 parts by mass of polyols, excessive progress of the resinification reaction can be suppressed, and the resination reaction and the foaming reaction can be prevented. Balance is maintained. Therefore, the distortion of the foam based on the rapid and unbalanced progress of the resinification reaction and the foaming reaction is effectively suppressed.

The effects exhibited by the above embodiment will be described below.
-In the polyurethane foam in this embodiment, by using 5 to 9 parts by mass per 100 parts by mass of polyols so as to increase water as a foaming agent, foaming is promoted and the apparent density is 16 to 22 kg / m. A polyurethane foam having a low density of ³ can be obtained. In addition, by using a predetermined amount of the specific amine catalyst and the metal catalyst as the catalyst, excessive progress of the resinification reaction is suppressed, and the balance between the resinification reaction and the foaming reaction is maintained. Therefore, it is possible to improve the strain characteristics represented by the compressive residual strain for the low-density foam. Furthermore, repeated compression residual strain can be improved.

  -By using a polyalkylene polyol having a polyethylene oxide unit content of 4 to 12 mol% as the polyol, the reactivity of the resinification reaction can be enhanced, and in particular, the initial resinification reaction can be assisted. it can.

  ・ By using sulfate hydrate as the hydrate of the inorganic compound, the sulfate hydrate is decomposed along the foaming process of the raw material of polyurethane foam to produce water and has good endothermic effect. Can be demonstrated.

Hereinafter, the embodiment will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. About the amine catalyst used in each Example and Comparative Example, resination activity constant (indicated by K ₁ ), foaming activity constant (indicated by K ₂ ), and ratio of foaming activity constant / resinization activity constant (K ₂ / K ₁ ) is shown in Table 1.

（実施例１〜４及び比較例１、２）
まず、各実施例及び比較例で用いたポリウレタン発泡体の原料を以下に示す。

(Examples 1 to 4 and Comparative Examples 1 and 2)
First, the raw material of the polyurethane foam used by each Example and the comparative example is shown below.

Polyol # 3000 (hetero): Polyether polyol obtained by addition polymerization of propylene oxide and ethylene oxide (8%) to glycerin. Molecular weight 3000, hydroxyl group number 3, hydroxyl value 56 (mgKOH / g), Sanyo Chemical Industries ( Co., Ltd., polyol GP-3050F
Dihydrate gypsum: specific gravity 2.32, dihydrate gypsum with an average particle size of 40 μm, manufactured by Noritake Co., Ltd. Catalyst 33LV: triethylenediamine, amine compound, Chukyo Yushi Co., Ltd. LV33: mass of triethylenediamine and propylene glycol Catalyst comprising a mixture having a ratio of 1: 2, Catalyst A-1 manufactured by Chukyo Yushi Co., Ltd. Catalyst A-1: Equivalent to N, N, N ′, N ″ -pentamethyldiethylenetriamine, Catalyst TOYOCAT HPW manufactured by GE Toshiba Methyl-N'-hydroxyethylpiperazine Catalyst TOYOCAT NEM: N-ethylmorpholine Catalyst TOYOCAT DAEM: N- (N ', N'-2-dimethylaminoethyl) morpholine Catalyst TOYOCAT D60: Aliphatic monoamine Catalyst TOYOCAT TEA: Triethylamine Agent BF2370: Silicone, Metal catalyst MRH-110: Dibutyltin dilaurate, Johoku Chemical Industry Co., Ltd. Polyisocyanate T-80: Tolylene diisocyanate (80% by mass of 2,4-tolylene diisocyanate and 20% by mass of 2,6-tolylene diisocyanate) ), Manufactured by Nippon Polyurethane Industry Co., Ltd. And raw materials for polyurethane foam in each example were prepared at the blending ratio shown in Table 2. Here, in Comparative Example 1, dihydrate gypsum as a hydrate of an inorganic compound Example 2 using two types of amine catalysts (Catalyst 33LV and Catalyst A-1) as catalysts, Example corresponding to Example 11-2 in Patent Document 1 and Comparative Example 2 using only triethylamine as a catalyst An example is shown.

These polyurethane foam raw materials are poured into foam containers of 500 mm in length, width, and depth, foamed at room temperature and atmospheric pressure, and then cured (crosslinked) by passing through a heating furnace to be softened. A slab foam was obtained. The obtained soft slab foam was cut out to produce a sheet-like polyurethane foam. With respect to this polyurethane foam, the apparent density, hardness, number of cells, rebound resilience, tensile strength, elongation, tear strength, compression residual strain and maximum exothermic temperature were measured according to the following measuring methods. The results are shown in Table 2.
(Measuring method)
Apparent density (kg / m ³ ): Measured according to JIS K 7222: 1999.

Hardness (N): Measured according to JIS K 6400-2: 2004.
Tensile strength (kPa), elongation (%) and tear strength (N / cm): Measured according to JIS K 6400-5: 2004.

Compression residual strain (%): Measured according to JIS K 6400-4: 2004.
Aeration rate (L / min): Measured according to ASTM D3574.
Maximum exothermic temperature (° C.): A thermocouple was inserted in the center of the foaming container, and the highest temperature increased during foaming and reaction was shown.

実施例１〜４においては、触媒として樹脂化活性定数が０．２２×１０〜０．９３×１０でかつ泡化活性定数／樹脂化活性定数の比が０．４７〜３．００×１０^−１であるアミン触媒及び金属触媒であるジブチルスズジラウレートをポリオール１００質量部当たり０．２５質量部含有している。このため、表２に示したように、特に圧縮残留歪を４．６〜６．０％に抑えることができた。

In Examples 1 to 4, the resinization activity constant as a catalyst is 0.22 × 10 to 0.93 × 10 and the ratio of the foaming activity constant / resinization activity constant is 0.47 to 3.00 × 10 ^{− The} amine catalyst which is ¹ and dibutyltin dilaurate which is a metal catalyst are contained in an amount of 0.25 parts by mass per 100 parts by mass of the polyol. For this reason, as shown in Table 2, it was possible to suppress the compression residual strain to 4.6 to 6.0%.

On the other hand, a catalyst A-1 having a resination activity constant of 4.26 × 10 and a ratio of foaming activity constant / resinization activity constant of 37.3 × 10 ⁻¹ and resinization activity constant of 3.63 × In Comparative Example 1 using a catalyst 33LV having a ratio of foaming activity constant / resinification activity constant of 10.34 × 10 ⁻¹ , the compression residual strain is a large value of 32.0%, which is practical. There was no sex. Further, in Comparative Example 2 using the catalyst TOYOCAT TEA in which the ratio of the foaming activity constant / resinization activity constant is 5.18 × 10 ⁻¹ , the compression residual strain is larger than those in Examples 1 to 4. The value was 11.0%.
(Comparative Examples 3 to 9)
A polyurethane foam was produced in the same manner as in Comparative Example 1 except that the type of catalyst was changed to that shown in Table 3 and the content was changed to 0.05 parts by mass per 100 parts by mass of polyol. The resulting polyurethane foam was measured for apparent density, hardness, number of cells, impact resilience, tensile strength, elongation, tear strength, compression residual strain and maximum exothermic temperature, and the results are shown in Table 3. . The description of the catalyst in Table 3 is shown below.

Catalyst TOYOCAT NP: N- (2-dimethylaminoethyl) -N'-methylpiperazine Catalyst TOYOCAT TE: N, N, N ', N'-tetramethylethylenediamine Catalyst TOYOCAT DT: N, N, N', N "- Pentamethyldiethylenetriamine Catalyst TOYOCAT ETS: Bis (2-dimethylaminoethyl) ether Catalyst TOYOCAT RX-3: N, N-dimethylaminoethoxyethanol Catalyst TOYOCAT RX-5: N, N, N'-trimethylaminoethylethanolamine

比較例３〜９におけるアミン触媒は、樹脂化活性定数が０．２２×１０〜０．９３×１０という条件及び泡化活性定数／樹脂化活性定数の比が０．４７〜３．００×１０^−１という条件のいずれか又は双方を満たしていない。そのため、表３に示したように、特に圧縮残留歪が１１．０〜１８．０という高い値を示した。
（実施例５〜８）
触媒の種類及び含有量を表４に示すように変更するとともに、発泡剤としての水の含有量をポリオール１００質量部当たり７．０質量部及び８．０質量部に変更した以外は実施例１と同様にして実施し、ポリウレタン発泡体を製造した。得られたポリウレタン発泡体について、見掛け密度、硬さ、セル数、反発弾性率、引張強さ、伸び、引裂強さ、圧縮残留歪及び最高発熱温度を測定し、それらの結果を表４に示す。

In the amine catalysts in Comparative Examples 3 to 9, the resinization activity constant was 0.22 × 10 to 0.93 × 10 and the ratio of foaming activity constant / resinization activity constant was 0.47 to 3.00 × 10. Either or both of the conditions of ^-1 is not satisfied. Therefore, as shown in Table 3, the compression residual strain showed a high value of 11.0 to 18.0.
(Examples 5 to 8)
Example 1 except that the type and content of the catalyst were changed as shown in Table 4, and the content of water as a blowing agent was changed to 7.0 parts by weight and 8.0 parts by weight per 100 parts by weight of polyol. In the same manner as above, a polyurethane foam was produced. The resulting polyurethane foam was measured for apparent density, hardness, number of cells, impact resilience, tensile strength, elongation, tear strength, compressive residual strain and maximum exothermic temperature, and the results are shown in Table 4. .

実施例５〜８では、発泡剤としての水を実施例１〜４に比べて増量させたが、触媒として樹脂化活性定数が０．６１×１０でかつ泡化活性定数／樹脂化活性定数の比が１．８６×１０^−１のＴＯＹＯＣＡＴ ＨＰＷ又は樹脂化活性定数が０．２２×１０でかつ泡化活性定数／樹脂化活性定数の比が０．４７×１０^−１のＴＯＹＯＣＡＴ ＮＥＭを使用した。そのため、表４に示すように、特に圧縮残留歪を６．８〜７．０に抑えることができた。
（実施例９〜１１及び比較例１０、１１）
実施例９では、実施例１において、ポリオール類として#3000(hetero)７０質量部に下記に示す#3000(homo)３０質量部を加え、エチレンオキシドの含有量を４．５質量％に設定した。実施例１０及び１１では金属触媒 MRH-110の含有量を表５に示すように変更した。一方、比較例１０では、実施例１において、触媒としてＡ−１のみを使用した。比較例１１では、比較例１において、触媒３３ＬＶを０．０１５質量部及び触媒Ａ−１を０．０１質量部に半減させ、その他は比較例１と同様にして実施し、ポリウレタン発泡体を製造した。得られたポリウレタン発泡体について、見掛け密度、硬さ、セル数、反発弾性率、引張強さ、伸び、引裂強さ、圧縮残留歪及び最高発熱温度を測定し、それらの結果を表５に示す。

In Examples 5 to 8, the amount of water as a foaming agent was increased as compared with Examples 1 to 4, but the resinization activity constant was 0.61 × 10 and the foaming activity constant / resinization activity constant was the catalyst. A TOYOCAT HPW with a ratio of 1.86 × 10 ⁻¹ or a TOYOCAT NEM with a resinization activity constant of 0.22 × 10 and a ratio of foaming activity constant / resinization activity constant of 0.47 × 10 ⁻¹ was used. . Therefore, as shown in Table 4, it was possible to suppress the compression residual strain to 6.8 to 7.0 in particular.
(Examples 9 to 11 and Comparative Examples 10 and 11)
In Example 9, 30 parts by mass of # 3000 (homo) shown below was added to 70 parts by mass of # 3000 (hetero) as a polyol in Example 1, and the content of ethylene oxide was set to 4.5 mass%. In Examples 10 and 11, the content of the metal catalyst MRH-110 was changed as shown in Table 5. On the other hand, in Comparative Example 10, only A-1 was used as the catalyst in Example 1. Comparative Example 11 is the same as Comparative Example 1 except that the catalyst 33LV is halved to 0.015 parts by mass and the catalyst A-1 is halved to 0.01 parts by mass. did. The resulting polyurethane foam was measured for apparent density, hardness, cell number, impact resilience, tensile strength, elongation, tear strength, compression residual strain and maximum exothermic temperature, and the results are shown in Table 5. .

  Polyol # 3000 (homo): Polyether polyol obtained by addition polymerization of propylene oxide to glycerin, molecular weight 3000, number of hydroxyl functional groups 3, hydroxyl value 56 (mgKOH / g), manufactured by Sanyo Chemical Industries, GP-3000NS

表５に示す結果から実施例９及び１０では、圧縮残留歪について実施例１とほぼ同様の結果を得た。実施例１１では、金属触媒の含有量を増加させたことにより、圧縮残留歪が実施例１に比べて若干増大し、９．５％になった。一方、本発明の範囲外の触媒Ａ−１のみを使用した比較例１０では圧縮残留歪が１６．０％、比較例１１では圧縮残留歪が１８．０％に達した。

From the results shown in Table 5, in Examples 9 and 10, substantially the same results as in Example 1 were obtained for the compression residual strain. In Example 11, as the content of the metal catalyst was increased, the compressive residual strain slightly increased compared to Example 1 to 9.5%. On the other hand, in Comparative Example 10 using only the catalyst A-1 outside the scope of the present invention, the compression residual strain reached 16.0%, and in Comparative Example 11, the compression residual strain reached 18.0%.

In addition, this embodiment can also be changed and embodied as follows.
As the catalyst, it is possible to use together an amine catalyst in which the ratio of the resination activity constant by the titration method and the ratio of the foaming activity constant / resinization activity constant does not fall within the above range.

  As the hydrate of the inorganic compound, a plurality of types of hydrates, for example, calcium sulfate hydrate and magnesium sulfate hydrate can be combined and blended. In that case, the function of the hydrate of the inorganic compound can be exhibited in a wider temperature range, and the exothermic temperature at the time of reaction and foaming can be effectively reduced.

Further, the technical idea that can be grasped from the embodiment will be described below.
-The foaming activity constant by a titration method is 0.8 * 10-6.0 * 10, The polyurethane foam as described in any one of Claims 1-3 characterized by the above-mentioned. In this case, the effect of the invention according to any one of claims 1 to 3 can be improved.

  The polyurethane foam according to claim 3, wherein the sulfate hydrate is a calcium sulfate hydrate or a magnesium sulfate hydrate. In this case, in addition to the effect of the invention according to claim 3, the function of the hydrate of the inorganic compound can be effectively exhibited.

  The polyurethane foam according to any one of claims 1 to 3, wherein the content of the hydrate of the inorganic compound is 20 to 40 parts by mass per 100 parts by mass of the polyols. In this case, in addition to the effects of the invention according to any one of claims 1 to 3, the endothermic action by the hydrate of the inorganic compound can be sufficiently exhibited without impairing the physical properties of the foam.

Claims (3)

It is obtained by reacting, foaming and curing raw materials of polyurethane foam containing polyols, polyisocyanates, foaming agents, catalysts and hydrates of inorganic compounds, and measured in accordance with JIS K 7222: 1999. A polyurethane foam having an apparent density of 16-22 kg / m ³ ,
While using 5 to 9 parts by mass of water as the foaming agent per 100 parts by mass of polyols, the catalyst activity constant by titration method is 0.22 × 10 to 2.0 × 10 and the foaming activity constant / resinification is used as a catalyst. It contains an amine catalyst having an activity constant ratio of 0.4 × 10 ^{−1 to} 3.0 × 10 ⁻¹ and a metal catalyst, dibutyltin dilaurate, and the amine catalyst is added in an amount of 0.01 to 100 parts by weight per 100 parts by weight of polyols. A polyurethane foam comprising 0.5 part by mass and the metal catalyst in an amount of 0.1 to 0.4 part by mass per 100 parts by mass of polyols. The polyurethane foam according to claim 1, wherein the polyol is a polyalkylene polyol having a polyethylene oxide unit content of 4 to 12 mol%. The polyurethane foam according to claim 1 or 2, wherein the inorganic compound hydrate is a sulfate hydrate.