JP3631558B2 - Manufacturing method of flexible mold foam - Google Patents

Description

【００１３】
【表２】

【００１４】
実施例１〜６で得られたフォームは〔表１〕に示されるとおり、反発弾性率がクッション材として好ましい３０％以上４０％以下の範囲にあり、しかも乾熱残留歪率が１０％以下、湿熱残留歪率が１０％以下で硬度の温度依存性が小さく、しっとり感のあるモールドフォームが製造できた。
比較例１は、ポリエーテルポリオール（ａ１）の使用量が範囲を超えた場合であったが、高い反発弾性率となり、目的のフォームが得られなかった。
比較例２は、ポリエーテルポリオール（ａ２）の総量が範囲を越えた場合、比較例３は、ポリエーテルポリオール（ａ２−４）の水酸基価が高すぎる場合であったが、いずれの場合も硬度の温度依存性が大きくなった。比較例４は、ポリエーテルポリオール（ａ１）の水酸基価が高すぎた場合であったが、反発弾性率および湿熱残留歪率が高めで、且つしっとり感を持ったフォームを得ることができなかった。
【００１５】
【発明の効果】
本発明によって得られる軟質ウレタンフォームは、適度な全体密度と低い反発弾性率を有しているのでしっとりとした感触を持ち、しかも硬度の温度依存性が低く、且つ乾熱および湿熱残留歪率が低い。したがって、乗り物のシート、寝具、ソファーなど各種クッション材や、防音材、衝撃吸収材などとして有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a flexible mold foam having a low impact resilience, a low temperature dependence of hardness, and a low residual strain rate.
[0002]
[Prior art]
Flexible foams are widely used as cushioning materials for automobile seats, bedding, sofas, and other soundproofing materials and shock absorbers. This flexible polyurethane foam is usually obtained by reacting a polyol and polyisocyanate in the presence of a foaming agent such as water and then foaming the slab or mold, but until now it has imparted low resilience to the flexible polyurethane mold foam. Many proposals have been made to do this. For example, (1) a method of foaming using a polyol having a relatively low molecular weight as seen in JP-A-2-175713 and JP-A-3-124720, and (2) JP-A-6-49167. As disclosed in JP-A-2-84421, a method of foaming a urethane foam material by mixing a resin such as a melamine resin and a plasticizer is known.
[0003]
[Problems to be solved by the invention]
With the recent high-grade orientation of people's automobiles and furniture, there is a growing demand for cushioning materials that are of higher quality and that retain their high quality even in severe use over the long term. It was. However, in the technology belonging to the above (1), since the closed cell ratio of the foam is high, the rebound elastic modulus is increased by opening the closed cell membrane under the actual use conditions accompanied by deformation such as repeated compression. In the technology belonging to (2), there is a problem that the foam becomes brittle due to the mixing of other resins and plasticizers, and the physical strength such as tensile strength and tear strength is lowered. However, there is still a problem that it is difficult to obtain a foam having a small hardness dependency on temperature and a small residual strain rate.
[0004]
[Means for Solving the Problems]
The inventors have a moist feeling that the overall density required for a high-quality cushion material is 40 kg / m ³ or more and the rebound resilience is 40% or less, and the dry heat residual strain and wet heat residual strain are high. As a result of research aimed at producing a polyurethane foam having both physical properties of 10% or less and low hardness temperature dependence, the average number of functional groups was 2 to 5, and the hydroxyl value was 20 mgKOH / g to 60 mgKOH / g. A polyol having a specific amount of polyol and an average functional group number of 1.5 to 4.5 and having a hydroxyl value of 90 mgKOH / g to less than 200 mgKOH / g, and having a hydroxyl value of 34 mgKOH / g to 130 mgKOH / g of the mixture ( a) and polyisocyanate (B) are reacted in the presence of a blowing agent (C) and the crosslinking agent, 80 ° C. or more foam after completion 50 ° C. or higher The inventors have found that a flexible polyurethane foam obtained by curing within 1 to 30 minutes has all of the above-mentioned physical properties, and further researched to complete the present invention. That is, the present invention
(1) The polyol (A-1) having an average functional group number of 2 to 5 and a hydroxyl value of 20 mgKOH / g to 60 mgKOH / g is 50% to 80% by weight, and the average functional group number is 1.5 to 4.5. A polyol (A) having a hydroxyl value of 90 mgKOH / g or more and less than 200 mgKOH / g and a polyol (A) having a hydroxyl value of 34 mgKOH / g or more and 130 mgKOH / g or less. isocyanate (B) a foaming agent (C) and reacted in the presence of a crosslinking agent, foaming after completion 50 ° C. or higher 80 ° C. or less, the production of flexible molded foam, characterized in Rukoto cured within 30 minutes more than one minute Law,
(2) The polyol (A-1) having an average functional group number of 2.5 to 3.5, a hydroxyl value of 30 mgKOH / g to 60 mgKOH / g, and an ethylene oxide unit content of 5% to 90% by weight (1) The production method according to
(3) The production method according to the above (1), wherein the polyol (A-2) has an average functional group number of 2 or more and 3 or less and a hydroxyl value of 110 mgKOH / g or more and 160 mgKOH / g or less,
(4) The production method according to any one of (1) to (3), wherein the polyol (A) has a hydroxyl value of 46 mgKOH / g or more and 100 mgKOH / g or less, (5) a foaming agent (C) The production method according to the above (1), wherein is water.
(6) The production method according to the above (5), wherein the amount of water used is 1 part by weight or more and 4 parts by weight or less based on 100 parts by weight of the polyol (A), and (7) polyisocyanate (B) is tolylene diene. The production method according to (1) above, which is a mixture of isocyanate or tolylene diisocyanate and polymethylene polyphenyl polyisocyanate,
It is.
[0005]
Examples of the polyols (A), (A-1) and (A-2) used in the present invention include those conventionally used in the production of polyurethanes, such as polyether polyols, and vinyl among these polyols. Examples include polymer polyols obtained by polymerizing monomers.
Examples of polyether polyols include alkylene oxide adducts such as alcohols, amines and ammonia. Examples of the alcohols include monohydric alcohols (methanol, ethanol, etc.), dihydric alcohols (ethylene glycol, propylene glycol, etc.), trihydric alcohols (glycerin, trimethylolpropane, etc.), tetrahydric alcohols, octavalent alcohol, and the like. Examples thereof include polyhydric alcohols such as alcohols. Examples of amines include monovalent amines (dimethylamine, diethylamine, etc.), divalent amines (methylamine, ethylamine, etc.), trivalent amines (monoethanolamine, diethanolamine, triethanolamine, etc.), and tetravalent amines. And polyvalent amines. Examples of the alkylene oxide include ethylene oxide (EO), propylene oxide (PO), 1,2-, 1,4- and 2,3-butylene oxide, and two or more of these may be used in combination. Among these, preferred are propylene oxide and / or ethylene oxide, and the addition type in the case of combined use may be either block or random.
[0006]
Examples of the polymer polyol include those obtained by polymerizing vinyl monomers such as acrylonitrile and styrene in the presence of radicals in the polyols exemplified above and stably dispersing them. The content of the vinyl monomer in the polymer polyol is usually 15% or more and 45% or less.
A thing preferable as a polyol (A-1) is a polyether polyol and / or a polymer polyol. The average functional group number of this polyol (A-1) is usually 2 or more and 5 or less, preferably 2.5 or more and 3.5 or less, and the hydroxyl value is usually 20 mgKOH / g or more and 60 mgKOH / g or less, preferably 30 mgKOH / g. It is 60 mgKOH / g or less. When the hydroxyl value is less than 20 mgKOH / g, it is difficult to produce a polyurethane foam and it is difficult to obtain a polyether polyol as a commercial product. If it exceeds 60 mgKOH / g, the resin forming the polyurethane foam becomes hard and a moist feel cannot be obtained. The ethylene oxide unit content of the polyol (A-1) is preferably 5% by weight or more and 90% by weight or less, more preferably 10% by weight or more and 80% by weight or less, and the terminal primary hydroxyl group% is 50%. % To 80% is preferable, and 60% to 75% is more preferable.
The average number of functional groups of the polyol (A-2) is usually 1.5 or more and 4.5 or less, preferably 2 or more and 3 or less, and the hydroxyl value is usually 90 mgKOH / g or more and less than 200 mgKOH / g, preferably 110 mgKOH / g or more. It is 160 mgKOH / g or less. When the hydroxyl value is less than 90 mgKOH / g, the impact resilience increases, and when it exceeds 200 mgKOH / g, the temperature dependence of the hardness increases.
The hydroxyl value of the polyol (A) comprising the polyols (A-1) and (A-2) is usually from 34 mgKOH / g to 130 mgKOH / g, preferably from 46 mgKOH / g to 100 mgKOH / g.
The mixing ratio of the polyols (A-1) and (A-2) is usually 50% by weight to 80% by weight: 20% by weight to 50% by weight, preferably 60% by weight to 70% by weight: 30% by weight or more and 40% by weight or less.
[0007]
As the polyisocyanate (B), known ones conventionally used for the production of flexible urethane foams, such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), phenylene diisocyanate (PDI), naphthalene diisocyanate (NDI) And free polyisocyanate-containing prepolymers obtained by reacting excess polyisocyanates with low molecular polyols, and the like. These can be used alone or in combination of two or more. In the present invention, TDI alone or a mixture of TDI and crude MDI is preferably used.
Examples of the blowing agent (C) used in the present invention include water and halogen-substituted aliphatic hydrocarbon blowing agents such as trichlorofluoromethane, dichlorodifluoromethane, trichloroethane, trichloroethylene, tetrachloroethylene, methylene chloride, trichlorotrifluoroethane, and dibromo. Examples include tetrafluoroethane and carbon tetrachloride. Of these blowing agents, water is preferred.
In the method of the present invention, in addition to the above components, a catalyst, a crosslinking agent, a foam stabilizer, and other auxiliary agents may be used as necessary.
[0008]
As the catalyst, known ones usually used in the production of polyurethane foam, for example, tertiary amines (triethylamine, triethylenediamine, N-methylmorpholine, etc.), quaternary ammonium salts (tetraethylhydroxylammonium, etc.), imidazoles (imidazole) Amine-based catalysts such as 2-ethyl-4-methylimidazole), organotin catalysts such as organic tin compounds (tin acetate, tin octylate, etc.), organic lead compounds (lead octylate, lead naphthenate), etc. Can be mentioned. Of these, tertiary amines and imidazoles are preferred.
As the crosslinking agent, those which can be usually used for the production of polyurethane foams are used, and examples thereof include ethylene glycol, monoethanolamine, diethanolamine, triethanolamine, glycerin, trimethylolpropane and the like.
As the foam stabilizer, those which can be usually used for the production of polyurethane foams such as siloxaneoxyalkylene block copolymers are used. Examples thereof include L-5309 and L-5366 manufactured by Nihon Unicar Co., Ltd., manufactured by Torre Silicon Co., Ltd. SRX-274C, B-4113 manufactured by Goldschmidt Co., Ltd., and the like.
Examples of other auxiliaries include known flame retardants, colorants, plasticizers, and internal mold release agents used in the production of polyurethane foam.
The amounts of the polyisocyanate (B), the foaming agent (C), the catalyst, the crosslinking agent and the foam stabilizer used in 100 parts by weight of the polyol (A) in the production method of the present invention are as follows.
The amount of polyisocyanate (B) used is such that the NCO index is usually from 75 to 125, preferably from 85 to 115. The amount of the blowing agent (C) used is usually 1.5 parts by weight or more and 4 parts by weight or less, preferably 2 parts by weight or more and 3 parts by weight or less. If it exceeds 4 parts by weight, the density will be low, and it will be difficult to obtain a moist feel. The amount of the catalyst used is usually from 0.01 to 5 parts by weight, preferably from 0.5 to 3 parts by weight. The amount of the crosslinking agent used is usually from 0 to 10 parts by weight, preferably from 1 to 8 parts by weight. The amount of the foam stabilizer used is usually from 0 to 5 parts by weight, preferably from 1 to 3 parts by weight.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the embodiment of the molding method in the present invention, a polyol (A), a foaming agent (C), a mixture of a catalyst, a crosslinking agent, a foam stabilizer and other auxiliary agents as necessary, and a polyisocyanate (B) are predetermined. The mixture is stirred and stirred in a fixed mold. The mixing ratio of the polyisocyanate (B) and other components is such that the NCO index is usually 75 or more and 125 or less, preferably 85 or more and 115 or less. After the foaming is completed, it is cured at 50 ° C. or higher and 80 ° C. or lower, usually 1 minute or longer and 30 minutes or shorter, preferably 2 minutes or longer and 20 minutes or shorter.
[0010]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited by these. In addition, the numerical value of the foaming prescription column in the examples and comparative examples shown in [Table 1] and [Table 2] indicates parts by weight of each raw material where the total weight of the polyol is 100.
Production raw materials for mold foam used in Examples and Comparative Examples:
Polyol a1-1: PO + EO adduct of glycerin, EO unit content 17%, hydroxyl value 36 mg KOH / g, terminal primary OH% 74.5
a1-2: PO + EO adduct of glycerin, EO unit content 12%, polymer polyol obtained by polymerizing acrylonitrile in a polyol having a hydroxyl value of 34 mg KOH / g (acrylonitrile content 20%)
a1-3: PO / EO adduct of dipropylene glycol, EO unit content 80%, hydroxyl value 51 mgKOH / g
a1-4: PO + EO adduct of glycerin, EO unit content 7%, hydroxyl value 70 mgKOH / g
a2-1: EO adduct of resorcin, hydroxyl value 105 mgKOH / g, EO unit content 90%
a2-2: PO adduct of propylene glycol, hydroxyl value 110 mgKOH / g
a2-3: PO adduct of glycerin, hydroxyl value 160 mgKOH / g
a2-4: PO adduct of glycerin, hydroxyl value 250 mgKOH / g
Mixture of polyisocyanate b: TDI-80: crude MDI = 80: 20 (Takenate TM-20 manufactured by Takeda Pharmaceutical Co., Ltd.)
Catalyst d: 33% dipropylene glycol solution of triethylenediamine (TEDA L-33 manufactured by Tosoh Corporation)
Cross-linking agent e-1: diethanolamine e-2: glycerin PO adduct, hydroxyl value 940 mgKOH / g
e-3: EO adduct of trimethylolpropane, hydroxyl value 920 mgKOH / g
Foam stabilizer f-1: Silicone surfactant (Tegostarb B-4113, manufactured by Goldschmidt Co., Ltd.)
f-2: Silicone surfactant (NUC Silicone L-5309 manufactured by Nippon Unicar Co., Ltd.)
[0011]
Examples 1-6 and Comparative Examples 1-4
In the production of each mold foam, the number of grams obtained by multiplying the numerical values of the respective raw materials shown in [Table 1] and [Table 2] by 5.5 was used.
As a general operation, first, polyol (A), water (C), catalyst (D), crosslinking agent (E) and foam stabilizer (F) were uniformly mixed at a liquid temperature of 25 ° C. Polyisocyanate (B) was added thereto, and the mixture was stirred at a high speed of about 5000 RPM using a high-speed stirrer (homomixer) for 5 seconds, and injected into an aluminum standard mold (400 mm × 400 mm × 100 mm) for foaming. Cured at 60 ° C. for 5 minutes, the foam was removed from the mold and crushed.
Tests fried in [Table 1] and [Table 2] were carried out on the obtained flexible urethane mold foams, and the results are also shown in each table. The density, impact resilience, dry heat, and wet heat residual strain were in accordance with JIS K 6401, and the tensile strength, elongation, and tear strength were in accordance with JIS K 6301.
[0012]
[Table 1]

[0013]
[Table 2]

[0014]
As shown in [Table 1], the foams obtained in Examples 1 to 6 have a rebound resilience in the range of 30% or more and 40% or less which is preferable as a cushioning material, and the dry heat residual strain is 10% or less. The moist heat residual strain ratio was 10% or less, and the temperature dependence of hardness was small, and a mold foam with a moist feeling could be produced.
Although the comparative example 1 was a case where the usage-amount of polyether polyol (a1) exceeded the range, it became a high impact resilience and the target foam was not obtained.
Comparative Example 2 was when the total amount of polyether polyol (a2) exceeded the range, and Comparative Example 3 was when the hydroxyl value of polyether polyol (a2-4) was too high. The temperature dependence of became larger. Comparative Example 4 was a case where the hydroxyl value of the polyether polyol (a1) was too high, but it was not possible to obtain a foam having a high rebound resilience and wet heat residual strain and having a moist feeling. .
[0015]
【The invention's effect】
The flexible urethane foam obtained by the present invention has a moderate overall density and a low rebound resilience, so it has a moist feel, has low temperature dependence of hardness, and has a dry heat and wet heat residual strain ratio. Low. Therefore, it is useful as various cushioning materials such as vehicle seats, bedding, sofas, soundproofing materials, shock absorbing materials and the like.

Claims (7)

A polyol (A-1) having an average functional group number of 2 to 5 and a hydroxyl value of 20 mgKOH / g to 60 mgKOH / g is 50% to 80% by weight, the average functional group number is 1.5 to 4.5 and a hydroxyl group Polyol (A) and polyisocyanate (B) having a hydroxyl value of 34 mgKOH / g or more and 130 mgKOH / g or less, comprising a polyol (A-2) having a value of 90 mgKOH / g or more and less than 200 mgKOH / g. ) In the presence of a foaming agent (C) and a crosslinking agent , and cured after completion of foaming at 50 ° C. to 80 ° C. for 1 minute to 30 minutes . The polyol (A-1) has an average functional group number of 2.5 to 3.5, a hydroxyl value of 30 mgKOH / g to 60 mgKOH / g, and an ethylene oxide unit content of 5% to 90% by weight. Manufacturing method. The process according to claim 1, wherein the polyol (A-2) has an average functional group number of 2 to 3, and a hydroxyl value of 110 mgKOH / g to 160 mgKOH / g. The process according to any one of claims 1 to 3, wherein the polyol (A) has a hydroxyl value of 46 mgKOH / g or more and 100 mgKOH / g or less. The process according to claim 1, wherein the foaming agent (C) is water. The production method according to claim 5, wherein the amount of water used is 1 part by weight or more and 4 parts by weight or less based on 100 parts by weight of the polyol (A). The process according to claim 1, wherein the polyisocyanate (B) is tolylene diisocyanate or a mixture of tolylene diisocyanate and polymethylene polyphenyl polyisocyanate.