KR100676118B1 - Semi-rigid polyurethane foam - Google Patents

Abstract

To provide a semi-rigid polyurethane foam that is difficult to produce fogging even at high temperature, and can be suitably used for automobile interior materials.

The haze value in the fogging test is 70% or more of strength retention at high temperature standing (120 ° C. × 24 hours standing), which is obtained by mixing and stirring a polyol mixture containing polyol, water, and a catalyst and polyisocyanate. A semi-hard polyurethane foam having two or less.

Description

Semi-rigid polyurethane foam {SEMI-RIGID POLYURETHANE FOAM}

The present invention relates to semi-rigid polyurethane foams. More specifically, the present invention relates to a semi-rigid polyurethane foam that can be suitably used for automobile interior materials such as headrests and armrests, in particular headrests formed by high-speed integral molding.

Semi-rigid polyurethane foams have been used as automotive interior materials because they have moderate shock absorbency, elasticity, compression recovery ratio and the like (Japanese Patent Laid-Open No. 8-143637, Japanese Patent Laid-Open No. 8-217847).

However, when these semi-rigid polyurethane foams are used as automotive interior materials, mainly due to the fact that amine catalysts are used in the production of semi-rigid polyurethane foams, when the temperature inside the automobile is high, the automobile is called fogging. Fog may occur on the windows.

It is an object of the present invention to provide a semi-rigid polyurethane foam in which fogging is unlikely to occur even at a high temperature and can be suitably used for automobile interior materials and the like.                         

The gist of the present invention is that the strength retention rate at the time of high temperature standing (120 ° C. × 24 hours standing), which is obtained by mixing and foaming a polyol mixture containing polyol, water, and a catalyst and polyisocyanate, in the fogging test It relates to a semi-hard polyurethane foam having a haze value of 2 or less.

The term "strength retention at high temperature standing (120 DEG C x 24 hours)" as used herein refers to JIS K6301 from the semi-rigid polyurethane foam after leaving the prepared semi-rigid polyurethane foam at room temperature for 24 hours. Ten specimens for measurement of tensile test of No. 2 were cut out, and five of the specimens were cut at room temperature using a tensile tester [Autoclave manufactured by Shimadzu Seisakusho Co., Ltd., product number: DCS-50M]. Average value of initial strength (initial strength) when tensile testing at a speed of 125 mm / min, and average value of tensile strength when tensile testing was performed in the same manner as described above after leaving the remaining five test specimens in an atmosphere at 120 ° C for 24 hours ( Strength at high temperature), and the formula:

[Intensity Retention Rate (%)] = [Intensity at High Temperature] ÷ [Initial Strength] × 100

Refers to the value obtained according to

Since the strength retention rate of the semi-rigid polyurethane foam of the present invention is 70% or more, it can be suitably used for automobile interior materials and the like. In addition, the strength retention ratio is preferably 80% or more from the viewpoint of preventing the foam strength from deteriorating with time.

In addition, the "haze value in a fogging test" as used in this specification means after leaving the manufactured polyurethane polyurethane foam for 1 day at room temperature, the test piece (50 mm x 50 mm x 100 mm) is cut out from the core part, and 2N The test piece was put into a 500 ml volumetric bottle containing 0.1 ml of hydrochloric acid, the opening was sealed with a transparent glass plate, and about 2/3 of this glass bottle was immersed in a bath kept at 80 ° C for 100 hours, and then the haze value of the glass plate was obtained. It is the value when it measures with haze meter (color difference meter) [manufactured by Nippon Denshoku Kogyo Co., Ltd., product number: NDH-20D]. In addition, a smaller haze value indicates a smaller degree of fog phenomenon.

Since the haze value of the semi-rigid polyurethane foam of the present invention is 2 or less, it is used in automobile interior materials and the like, and even when left at a high temperature in an enclosed space such as in an automobile, an excellent effect that no fogging occurs in a glass window or the like is expressed. This haze value is made 2 or less from a viewpoint of preventing fogging, Preferably it is 1 or less.

In addition, the foam density (core density, the same below) of the semi-hard polyurethane foam of the present invention is 25 to 100 kg / m 3, preferably 30 to 80 kg / m 3 from the viewpoint of foam strength and cushioning properties and weight reduction.

The semi-hard polyurethane foams of the present invention can be produced by mixing and stirring a polyol mixture containing a polyol, water and a catalyst and a polyisocyanate.

Examples of the polyols include polyester polyols and polyether polyols. The average hydroxyl value of the polyol is 14 to 100 mg KOH / g, preferably 17 to 75 mg KOH / g, more preferably 17 to 70 mg KOH / g from the viewpoint of imparting viscosity and elasticity to the foam.

As dicarboxylic acid used for a polyester-type polyol, Saturated aliphatic dicarboxylic acid, such as glutaric acid, adipic acid, pimelic acid, subberic acid, azelaic acid, sebacic acid; 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; These ester-forming derivatives, these acid anhydrides, etc. are mentioned, These can be used individually or in mixture of 2 or more types. In addition, the dicarboxylic acid may contain trifunctional or more than trifunctional polybasic acid, such as trimellitic acid and a pyromellitic acid, as needed.

Examples of the diol constituting the polyester-based polyol include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, methylpentanediol, 1,6-hexanediol, trimethylolpropane, and glycerin And pentaerythritol, diglycerin, dextrose, sorbitol, and the like, and these can be used alone or in combination of two or more thereof.

Representative examples of the polyether polyols include polyoxypropylene polyols (hereinafter referred to as PPG), polyoxytetramethylene glycol (hereinafter referred to as PTMG), and mixtures thereof. Among these, PPG to which ethylene oxide is added at the terminal is preferable. The ratio (weight ratio) of polyoxypropylene / polyoxyethylene of PPG is preferably 50/50 to 95/5, more preferably 60/40 to 80/20 from the viewpoint of hydrolyzability and reactivity and foam strength.

PPG can be produced by a compound having two or more active hydrogen atoms as a starting material, by adding a ethylene oxide to the molecular end in a block-opening reaction of a normal alkylene oxide.

As a compound which has two or more active hydrogens, polyhydric alcohol, polyhydric phenol, a polyamine, an alkanolamine, etc. are mentioned. 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, diglycerin, dextrose, sucrose, bisphenol A, ethylenediamine, modified products thereof and the like, and these may 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 1000 or more.

It is possible to contain a foam stabilizer in the polyol mixture as needed. In general, the foam stabilizer may be one used when producing a polyurethane foam. Examples of the foam stabilizer include silicone-based surfactants such as dimethylpolysiloxane and polyoxyalkylene-modified dimethylpolysiloxane, and anionic surfactants such as fatty acid salts, sulfate ester salts, phosphate ester salts, and sulfonate salts.

Since the amount of foam stabilizer is different depending on the kind or the density of the foam of the semi-hard polyurethane foam to be used, it cannot be determined uniformly. Therefore, it is preferable to adjust the foam stabilizer appropriately according to the type of foam stabilizer. For example, it is preferable to use 0.2-3 parts of foam stabilizers with respect to 100 weight part of polyols (it abbreviate | omits below).

Water is used as a blowing agent. As long as the object of the present invention is not impaired in addition to water, low boiling point hydrocarbons such as isopentane, normal pentane and cyclopentane, nitrogen gas, air, gases such as carbon dioxide, HCFC-141b, HFC-134a, HFC-245fa, and HFC A blowing agent such as -245ca, HFC-236ea, or HFE-347 may be used.

Since the amount of water depends on the foam density of the target semi-hard polyurethane foam, it cannot be determined uniformly, and it is preferable to adjust suitably according to the target foam density.

As a catalyst, the amine catalyst which has a primary hydroxyl group in a molecule | numerator is preferable. As an amine catalyst, amines, such as dimethylaminoalkyl alcohol and dimethylaminoalkoxy alcohol represented by following formula (I), are mentioned, These can be used individually or in mixture of 2 or more types.

[Formula I]

(CH ₃ ) ₂ N- (CH ₂ ) _p -OH

(Wherein p represents an integer of 4 to 8)

In these, since the dimethylamino alkyl alcohol represented by General formula (I) is excellent in the effect which prevents fogging, it can be used suitably. It is also possible to use organic metal compounds such as dibutyl tin dilaurate, first tin oleate, cobalt naphthenate and lead naphthenate together with the amine.

6-dimethylamino-1-hexanol, 4-dimethylamino-1-butanol, 8-dimethylamino-1-octanol, etc. are mentioned as dimethylamino alkyl alcohol. Dimethyl amino ethoxy ethanol, dimethyl amino ethoxy ethoxy ethanol etc. are mentioned as dimethyl amino alkoxy alcohol. Of these, 6-dimethylamino-1-hexanol can be suitably used because of its high strength retention.

The amount of the catalyst is 0.5 to 6 parts, preferably 1 to 4 parts from the viewpoint of deforming properties, filling properties, and moldability with respect to 100 parts of polyol.

Preferred ratios of the polyol, water and catalyst are 2 to 8 parts of water and 0.5 to 6 parts of catalyst with respect to 100 parts of polyol, and more preferably 2.5 to 4.5 parts of water and 1 to 4 parts of catalyst.

In addition, you may add a crosslinking agent, a stabilizer, a pigment, etc. to an appropriate amount in a polyol mixture as needed.

As a crosslinking agent, the low molecular weight compound etc. which have two or more active hydrogen containing groups which can react with a hydroxyl group, a primary amino group, a secondary amino group, and another isocyanate group are mentioned. Examples thereof include alkylene oxide addition of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin, trimethylolpropane, triethanolamine, and bisphenol A. Polyamines, such as polyhydric alcohols, such as water, diethyltoluenediamine, chlorodiaminobenzene, ethylenediamine, and 1, 6- hexanediamine, etc. are mentioned, These can be used individually or in mixture of 2 types of paper.

Examples of stabilizers include dibutylhydroxytoluene, pentaerythryl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], isooctyl-3- (3, Hindered phenol radical scavengers such as 5-di-t-butyl-4-hydroxyphenyl) propionate; Antioxidants such as phosphorous acid compounds such as phosphorous acid, triphenyl phosphite, triethyl phosphite and triphenyl phosphine; 2- (5-methyl-2-hydroxyphenyl) benzotriazole, methyl-3- [3-t-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl] propio And ultraviolet absorbers such as condensates of nate and polyethylene glycol, and the like, and these can be used alone or in combination of two paper forms. Among these stabilizers, the phosphorous acid compound, in particular triphenylphosphite and pentaerythritol-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], has a foam strength. It can be suitably used in view of improvement. In particular, the foam strength is further enhanced when triphenyl phosphite and pentaerythritol-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] are used in combination. There is an advantage that it can be improved.

Examples of the pigment include inorganic pigments represented by transition metal salts, organic pigments represented by azo compounds, carbon powders, and the like. These pigments may be used alone or in combination of two paper forms.

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. As this specific example, Aromatic polyisocyanate, such as a triylene diisocyanate, a methylene diphenyl diisocyanate, a naphthylene diisocyanate, a xylylene diisocyanate, a polymethylene polyphenylene isocyanate; Alicyclic polyisocyanates such as water added methylene diphenyl diisocyanate, water added triylene diisocyanate and isophorone diisocyanate; Aliphatic polyisocyanates such as hexamethylene diisocyanate and lysine diisocyanate; Mixtures thereof; These modified bodies etc. are mentioned. As a modified body, the prepolymer type modified body which is a reaction product of polyisocyanate and a polyol, a nurate modified body, a urea modified body, a carbodiimide modified body, an allophanate modified body, a biuret modified body, etc. are mentioned.

As a method of producing a semi-hard polyurethane foam, a polyol mixture obtained by mixing and stirring other additives such as polyol, water, a catalyst, and a foam stabilizer in advance, and a polyisocyanate are mixed and stirred with a molding machine, and injected into a molding die. And foaming. More specifically, after mixing and stirring the polyol mixture by using a tank or the like, the temperature is usually adjusted to about 20 ° C., and then reacted with the polyisocyanate compound and foamed using a foamer such as an automatic mixed injection foaming machine or an automatic mixed injection foaming machine. And the like.

In addition, it is preferable to adjust the ratio of a polyol and polyisocyanate so that an isocyanate index may be 95-110 normally.

As described above, the semi-rigid polyurethane foam of the present invention has a high strength retention rate and a low haze value, and thus can be suitably used as automobile interior materials such as headrests and armrests.

(Example)

Examples 1-3 and Comparative Examples 1-3

Branched polyether polyol which is PPG with ethylene oxide added to the terminal (average hydroxyl value: 28 mg KOH / g, manufactured by Sumitomo Bayer Urethane Co., Ltd., product name: Simifen 3063), 100 parts of triethanolamine, 1.5 parts of blowing agent 3.6 parts of water, and the catalyst and the additive of the composition shown in Table 1 were mixed by a labomixer to obtain a polyol mixture.

The resulting polyol mixture and polyisocyanate (manufactured by Sumitomo Bayer Urethane Co., Ltd., trade name: Sumidule 44V 20) were mixed and stirred with a labomixer at 15 ° C. such that the isocyanate index was 105, and 250 g of the obtained mixture was molded ( Inner dimension: 150 x 150 x 300 (height) mm) was injected to form a pre-foam of a semi-rigid polyurethane foam.

In addition, strength retention and haze value of the obtained semi-hard polyurethane foam were investigated based on the above method. In addition, the foam density was investigated based on the following method. The results are shown in Table 1.

(Foam density)

After preparing the pre-foamed product of the semi-hard polyurethane foam and leaving it for one day, the test piece of 100 mm x 100 mm x 100 mm size is cut out from this core part, and the weight of this test piece is measured and divided into its volume.

Example number Catalyst (part) Additive (part) Strength retention rate (%)  Haze value  Core density of foam (㎏ / ㎥) One Dimethylaminoethoxyethanol (3.5) PETP ^{* 1} (0.2) Triphenylphosphite (0.2)  75.8  0.8  52.6 2 Dimethylaminoethoxyethoxyethanol (3.5) PETP ^{* 1} (0.2) Triphenylphosphite (0.2)  70.5  0.7  53.7 3 6-dimethylamino-1-hexanol (3.5) - 85.9 0.2 53.2 Comparative Example 1 33.3% diethylene glycol solution of triethylenediamine (3.4) - 103.2 15.8 52.3 2 N, N, N ', N'-tetramethylhexanediamine (2.4) - 102.2 36.0 53.6 3 Trimethylaminopropylethanolamine (3.5) - 49.0 0.7 53.1 * 1: pentaerythritol-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]

From the results shown in Table 1, it can be seen that the semi-hard polyurethane foams obtained in Examples 1 to 3 have high strength retention and very small haze value, so that fogging rarely occurs, and thus it can be suitably used as an automotive interior material. have.

Since the semi-hard polyurethane foam of this invention has moderate intensity | strength without generating fogging even at high temperature, it can be used suitably as an automotive interior material etc.                     

Claims (8)

In the amount of 0.5 to 6 parts by weight based on 100 parts by weight of the polyol, water, and polyol: [Formula I] (CH ₃ ) ₂ N- (CH ₂ ) _p -OH (Wherein p represents an integer of 4 to 8) The strength retention ratio at the time of high temperature standing (120 degreeCx24 hours standing) made by mixing, stirring, and foaming the polyol mixture containing dimethylamino alkyl alcohol and polyisocyanate represented by the above is a haze value in a fogging test. Semi-hard polyurethane foams of 2 or less. The semi-hard polyurethane foam according to claim 1, wherein 2 to 8 parts by weight of water is used based on 100 parts by weight of polyol. The semi-hard polyurethane foam according to claim 1 or 2, wherein the foam density (core density) is 25 to 100 kg / m 3. The semi-hard polyurethane foam according to claim 1 or 2, wherein the polyol has an average hydroxyl group of 14 to 100 mg KOH / g. The semi-hard polyurethane foam according to claim 1 or 2, wherein the polyol is a polyoxypropylene-based polyol to which an ethylene oxide is added. The semi-hard polyurethane foam according to claim 5, wherein the polyoxypropylene-based polyol has a ratio (weight ratio) of polyoxypropylene / polyoxy ethylene of 50/50 to 95/5. delete 100 parts by weight of polyol, 2 to 8 parts by weight of water and the formula [Formula I] (CH ₃ ) ₂ N- (CH ₂ ) _p -OH (Wherein p represents an integer of 4 to 8) The polyol mixture containing 0.5 to 6 parts by weight of dimethylaminoalkyl alcohol and polyisocyanate mixed with agitation and foaming were subjected to a high temperature (120 ° C × 24 hours) strength retention ratio of 70% or more. A method for producing a semi-rigid polyurethane foam having a haze value of 2 or less.