JP2000319435A - Semi-rigid polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semi-rigid polyurethane foam hardly causing fogging even in a high temperature state and suitably employed as an interior material for an automobile or the like. SOLUTION: A polyol mixture comprising a polyol, water and a catalyst is mixed with a polyisocyanate with agitation and is foamed to give the objective foam, which has a retention of strength, when left at a high temperature (120 deg.C×24 hr) of at least 70% and a haze value of not more than 2 in a fogging test.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semi-rigid polyurethane foam. More specifically, the present invention relates to a semi-rigid polyurethane foam which can be suitably used for automobile interior materials such as headrests and armrests, particularly headrests formed by a high-speed integral molding method.

[0002]

2. Description of the Related Art Semi-rigid polyurethane foams are used as automobile interior materials because they have an appropriate shock absorption, elasticity, compression recovery ratio, etc. (Japanese Patent Application Laid-Open No. Hei 8-1436).
No. 37, JP-A-8-217847).

[0003] However, when these semi-rigid polyurethane foams are used as interior materials for automobiles, the temperature inside the automobile becomes high mainly because amine catalysts are used in the production of semi-rigid polyurethane foams. The fogging phenomenon may occur on the window glass of an automobile, which is called fogging.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a semi-rigid polyurethane foam which does not easily cause fogging even at a high temperature and can be suitably used as an automobile interior material or the like.

[0005]

The gist of the present invention is that a polyol mixture containing a polyol, water and a catalyst is mixed with a polyisocyanate, and the mixture is stirred and foamed. The mixture is left at a high temperature (120 ° C. for 24 hours). 70% strength retention
This is a semi-rigid polyurethane foam having a haze value of 2 or less in a fogging test.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The term "high temperature storage (12
"The strength retention at 0 ° C. × 24 hours)” means that the manufactured semi-rigid polyurethane foam is allowed to stand at room temperature for 24 hours and then subjected to JIS K
In accordance with 6301, No. 2 type test piece 1 for tensile test measurement
0 pieces were cut out, and five of the test pieces were pulled at room temperature using a tensile tester [Autograph manufactured by Shimadzu Corporation, product number: DCS-50M] at a tensile speed of 125.
The average value (initial strength) of the tensile strength at the time of the tensile test at mm / min and the strength of the tensile strength at the time of the tensile test in the same manner as described above after leaving the remaining five test pieces in an atmosphere at 120 ° C. for 24 hours. Measure the average value (strength at high temperature)
Formula: [Strength retention (%)] = [High temperature strength] ÷ [Initial strength]
× 100 refers to the value determined according to

Since the semi-rigid polyurethane foam of the present invention has a strength retention of 70% or more, it can be suitably used as an automobile interior material or the like. The strength retention is preferably 80% or more from the viewpoint of preventing the foam strength from deteriorating with time.

[0008] The term "haze value in fogging test" as used herein means that a manufactured semi-rigid polyurethane foam is allowed to stand at room temperature for one day, and a test piece (50 mm x 50 mm x 100 mm) is taken from its core. The test piece was placed in a 500 ml glass bottle containing 0.1 ml of 2N hydrochloric acid, the opening was sealed with a transparent glass plate, and about two thirds of the glass bottle was kept at 80 ° C. After immersion in a hot water bath for 100 hours, the haze value of the glass plate was measured with a haze meter (color difference meter) [Nippon Denshoku Industries Co., Ltd.
, Product number: NDH-20D]. The smaller the haze value, the lower the degree of fogging.

Since the haze value of the semi-rigid polyurethane foam of the present invention is 2 or less, even if it is used as an interior material of an automobile and is left at a high temperature in a closed space like an automobile, the haze value of the foam is small. An excellent effect of not generating fogging on glass or the like is exhibited. The haze value is set to 2 or less from the viewpoint of preventing fogging, but is preferably 1 or less.

The semi-rigid polyurethane foam of the present invention has a foam density (core density, the same applies hereinafter) of 25 to 25 from the viewpoint of foam strength, cushioning property and weight reduction.
100 kg / m ^3, it is desirable that preferably is 30~80kg / m ^3.

The semi-rigid polyurethane foam of the present invention comprises
It can be produced by mixing, stirring and foaming a polyol mixture containing a polyol, water and a catalyst, and a polyisocyanate.

Examples of the polyol include a polyester polyol and a polyether polyol. The average hydroxyl value of the polyol is from 14 to 100 mgKOH / g, preferably from 17 to 75 mgKOH / g, more preferably from 17 to 75, from the viewpoint of imparting elasticity to the viscosity and the foam.
Desirably, it is ７０70 mgKOH / g.

The dicarboxylic acids used in the polyester polyol include saturated aliphatic dicarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid; and saturated alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Aromatic dicarboxylic acids such as phthalic acid, terephthalic acid and isophthalic acid; unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid; halogen-containing dicarboxylic acids such as tetrabromophthalic acid; And acid anhydrides thereof, and these can be used alone or in combination of two or more. The dicarboxylic acid may optionally contain a trifunctional or higher polybasic acid such as trimellitic acid or pyromellitic acid.

The diols constituting the polyester polyol include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, methylpentanediol, 1,6-hexanediol, trimethylolpropane, Glycerin, pentaerythritol, diglycerin, dextrose, sorbitol and the like can be mentioned, and these can be used alone or in combination of two or more.

A typical example of the polyether polyol is a polyoxypropylene polyol (hereinafter referred to as PPG).
), Polyoxytetramethylene glycol (hereinafter referred to as PTMG), and mixtures thereof. Among them, PPG to which ethylene oxide is added at the terminal is preferable. PPG polyoxypropylene /
The ratio (weight ratio) of polyoxyethylene is preferably 50 from the viewpoint of hydrolyzability, reactivity and foam strength.
/ 50-95 / 5, more preferably 60 / 40-80 /
20.

PPG is produced by using a compound having two or more active hydrogen atoms as a starting material, subjecting the compound to a conventional ring-opening addition reaction of an alkylene oxide, and further adding ethylene oxide to the molecular terminal in a blockwise manner. be able to.

Examples of the compound having two or more active hydrogens include polyhydric alcohols, polyhydric phenols, polyamines and alkanolamines. Specific examples of the compound having two or more active hydrogens include ethylene glycol,
Diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,4-
Butanediol, 1,6-hexanediol, glycerin, trimethylolpropane, pentaerythritol,
Examples thereof include diglycerin, dextrose, sucrose, bisphenol A, ethylenediamine, and modified products thereof, and these can be used alone or in combination.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide and the like.

PTMG is obtained by ring-opening polymerization of tetrahydrofuran, and preferably has a number average molecular weight of 1,000 or more.

The polyol mixture may contain a foam stabilizer, if necessary. The foam stabilizer may be any one that is generally used when producing a polyurethane foam. Examples of foam stabilizers include silicone-based surfactants such as dimethylpolysiloxane and polyoxyalkylene-modified dimethylpolysiloxane, and anionic surfactants such as fatty acid salts, sulfates, phosphates, and sulfonates. No.

Since the amount of the foam stabilizer varies depending on its type and the desired foam density of the semi-rigid polyurethane foam, it cannot be unconditionally determined. Therefore, it is necessary to appropriately adjust the amount according to the kind of the foam stabilizer. Is desirable. For example, it is preferable to use 0.2 to 3 parts of the foam stabilizer with respect to 100 parts by weight of the polyol (hereinafter abbreviated as "part").

Water is used as a blowing agent. In addition to water, low-boiling hydrocarbons such as isopentane, normal pentane and cyclopentane, nitrogen gas, air, and gases such as carbon dioxide, HCFC-141b, and HFC-134a as long as the object of the present invention is not impaired. , H
FC-245fa, HFC-245ca, HFC-23
A foaming agent such as 6ea and HFE-347 may be used.

Since the amount of water varies depending on the desired foam density of the semi-rigid polyurethane foam and cannot be unconditionally determined, it is desirable to appropriately adjust the amount of water according to the desired foam density.

As the catalyst, an amine catalyst having a primary hydroxyl group in the molecule is preferable. Examples of the amine catalyst include: dimethylaminoalkyl alcohol represented by the formula (I): (CH ₃ ) ₂ N— (CH ₂ ) _p —OH (I) (where p is an integer of 4 to 8); Examples thereof include amines such as dimethylaminoalkoxy alcohol, and these can be used alone or in combination of two or more. Among them, dimethylaminoalkyl alcohol represented by the formula (I) has an excellent effect of preventing fogging,
It can be suitably used. Further, organic metal compounds such as dibutyltin dilaurate, stannous oleate, cobalt naphthenate, and lead naphthenate may be used in combination with the amine.

Examples of the dimethylaminoalkyl alcohol include 6-dimethylamino-1-hexanol, 4-dimethylamino-1-butanol and 8-dimethylamino-1
-Octanol and the like. Examples of the dimethylaminoalkoxy alcohol include dimethylaminoethoxyethanol, dimethylaminoethoxyethoxyethanol, and the like. Among these, 6-dimethylamino-
Since 1-hexanol has a high strength retention, it can be suitably used.

The amount of the catalyst is preferably from 0.5 to 6 parts, more preferably from 1 to 4 parts, from the viewpoint of demoldability, filling and moldability, based on 100 parts of the polyol.

The preferred proportions of the polyol, water and catalyst are 2 to 8 parts of water and 0.5 to 6 parts of catalyst, more preferably 2.5 to 4.5 parts of water, per 100 parts of polyol.
Parts and 1 to 4 parts of catalyst.

If necessary, for example, a crosslinking agent, a stabilizer, a pigment and the like may be appropriately added to the polyol mixture in an appropriate amount.

As a crosslinking agent, a hydroxyl group, a primary amino group,
Low molecular weight compounds having two or more active hydrogen-containing groups capable of reacting with secondary amino groups and other isocyanate groups are exemplified. Examples thereof include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin, trimethylolpropane, triethanolamine, and alkylene oxides of bisphenol A. Examples thereof include polyhydric alcohols such as adducts, and polyamines such as diethyltoluenediamine, chlorodiaminobenzene, ethylenediamine, and 1,6-hexanediamine. These can be used alone or in combination of two or more.

As the stabilizer, dibutylhydroxytoluene, pentaerythrityl-tetrakis [3- (3,5-di-t-t-
Butyl-4-hydroxyphenyl) propionate] and a hindered phenol radical scavenger such as isooctyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate; phosphorous acid, triphenylphosphite, triethyl Antioxidants such as phosphites and phosphites such as triphenylphosphine; 2- (5-methyl-2-hydroxyphenyl) benzotriazole, methyl-3- [3-t-butyl-5- (2H-benzo) Triazol-2-yl) -4-hydroxyphenyl] UV absorbers such as condensates of propionate and polyethylene glycol, and the like, and these can be used alone or as a mixture of two or more. Among these stabilizers, phosphite compounds, especially triphenyl phosphite and pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], have foam strength. From the viewpoint of improvement, it can be suitably used. In particular, triphenylphosphite and pentaerythrityl-tetrakis [3- (3,5-di
-t-butyl-4-hydroxyphenyl) propionate]
When used in combination with the above, there is an advantage that the foam strength can be further increased.

Examples of the pigment include inorganic pigments typified by transition metal salts, organic pigments typified by azo compounds, and carbon powder. These pigments may be used alone or in combination of two or more. Can be.

Examples of the polyisocyanate include aromatic, alicyclic and aliphatic polyisocyanates having two or more isocyanate groups, mixtures thereof, and modified polyisocyanates obtained by modifying them.
Specific examples thereof include aromatic polyisocyanates such as tolylene diisocyanate, methylene diphenyl diisocyanate, naphthylene diisocyanate, xylylene diisocyanate, and polymethylene polyphenylene isocyanate; hydrogenated methylene diphenyl diisocyanate;
Alicyclic polyisocyanates such as hydrogenated tolylene diisocyanate and isophorone diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate and lysine diisocyanate; mixtures thereof; modified products thereof; Examples of the modified product include a prepolymer-based modified product, a nurate-modified product, a urea-modified product, a carbodiimide-modified product, an allophanate-modified product, and a buret-modified product, which are reaction products of a polyisocyanate and a polyol.

As a method for producing a semi-rigid polyurethane foam, a polyol mixture obtained by previously mixing and stirring a polyol, water, a catalyst and, if necessary, other additives such as a foam stabilizer, and a polyisocyanate are molded. Mixing and stirring with a machine, injecting into a mold, and foaming. More specifically, the polyol mixture is mixed and stirred using a tank or the like, and the temperature is usually adjusted to about 20 ° C., and then the poly is mixed using a foaming machine such as an automatic mixing injection type foaming machine and an automatic mixing type injection foaming machine. A method of reacting and foaming with an isocyanate compound is exemplified.

The ratio between the polyol and the polyisocyanate is usually in the range of from 95 to 95%.
It is preferable to adjust so as to be 110.

As described above, since the semi-rigid polyurethane foam of the present invention has a high strength retention and a low haze value, it can be suitably used as an automobile interior material such as a headrest and an armrest.

[0036]

EXAMPLES Examples 1 to 3 and Comparative Examples 1 to 3 Branched polyether polyols, which are PPGs having ethylene oxide added to their terminals (average hydroxyl value: 28 mg)
KOH / g, manufactured by Sumitomo Bayer Urethane Co., Ltd., trade name:
Sumifen 3063), 100 parts of triethanolamine, 3.6 parts of water as a blowing agent, and a catalyst and an additive having the composition shown in Table 1 were mixed with a laboratory mixer to obtain a polyol mixture.

The obtained polyol mixture and a polyisocyanate (trade name: Sumidur 44V20, manufactured by Sumitomo Bayer Urethane Co., Ltd.) were mixed and stirred with a lab mixer at 15 ° C. so that the isocyanate index became 105. 250 g of the mixture obtained was molded into a mold (inner size: 150
× 150 × 300 (height) mm) to form a semi-rigid polyurethane foam free foam.

The strength retention and haze value of the obtained semi-rigid polyurethane foam were examined based on the above-mentioned methods. Further, the foam density was examined based on the following method. Table 1 shows the results.

[Foam Density] After producing a free foam of a semi-rigid polyurethane foam, leave it for one day, and then measure 100 mm × 100 mm × 100 mm from its core.
A test piece having a size of is cut out, and the weight of the test piece is measured, divided by its volume, and measured.

[0040]

[Table 1]

From the results shown in Table 1, since the semi-rigid polyurethane foams obtained in Examples 1 to 3 have high strength retention and a very small haze value, they hardly cause fogging. It turns out that it can be used suitably as a material.

[0042]

The semi-rigid polyurethane foam of the present invention does not generate fogging even at a high temperature and has an appropriate strength, so that it can be suitably used as an automobile interior material or the like.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayoshi Morii 1334 Minato, Wakayama-shi F-term in Kao Corporation Research Laboratories 4F074 AA79 AA80 AD13 AG20 BA34 CA12 CA23 CA25 DA02 DA08 DA16 DA24 DA35 4J034 CE01 DA01 DA03 DF01 DF14 DF16 DF20 DF21 DF22 DF27 DF35 DG01 DG02 DG04 DG06 DG14 DG23 HA01 HA06 HA07 HB06 HB07 HB08 HC01 HC02 HC03 HC11 HC12 HC13 HC22 HC46 HC52 HC54 HC61 HC63 HC64 HC65 HC66 HC67 HC71 HC73 KA01 KD12 QB18 QBQ14QB

Claims (5)

[Claims] 1. A polyol mixture containing a polyol, water and a catalyst and a polyisocyanate are mixed, stirred and foamed, and have a strength retention of 70% or more when left at a high temperature (120 ° C. × 24 hours). A semi-rigid polyurethane foam having a haze value of 2 or less in a fogging test. 2. 100 parts by weight of polyol and water 2
2. The semi-rigid polyurethane foam according to claim 1, wherein the foam comprises from 8 to 8 parts by weight. 3. A foam density (core density) of 25 to 10
^3. The semi-rigid polyurethane foam according to claim 1, wherein the weight is 0 kg / m ³ . 4. The semi-rigid polyurethane foam according to claim 1, wherein the catalyst is an amine catalyst having a primary hydroxyl group in a molecule. 5. A polyol mixture containing 100 parts by weight of a polyol, 2 to 8 parts by weight of water and 0.5 to 6 parts by weight of a catalyst and a polyisocyanate are mixed, stirred, foamed, and left at a high temperature (120 ° C. for 24 hours). 7) Strength retention rate when left unattended
0% or more, and the haze value in the fogging test is 2
A method for producing a semi-rigid polyurethane foam which produces the following semi-rigid polyurethane foam.