JP2006152182A - Polyol composition and method for producing semi-rigid polyurethane foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a low-density crash pad and a door trim with slight void defectives for a vehicular instrument panel. <P>SOLUTION: A polyol composition for producing a semi-rigid polyurethane foam is composed of a polymer polyol (A) and/or a polyol (B) obtained by polymerizing a vinylic monomer (b) in a polyol (a) and contains specific polyols (a1), (a2) and (a3) in the (a) and/or (B). A composition for forming the semi-rigid polyurethane foam composed of a polyisocyanate component, a foaming agent composed of water, a catalyst and, as necessary, a foam stabilizer is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyol composition for producing a semi-rigid polyurethane foam, a foam-forming composition, and a method for producing a polyurethane foam using the same. More specifically, the present invention relates to a polyol composition for producing a semi-rigid polyurethane foam suitable for interior members such as a crash pad of a vehicle instrument panel, a foam-forming composition, and a method for producing a polyurethane foam using the same.

Conventionally, semi-rigid polyurethane foams have been widely used as interior members such as crash pads for instrument panels of automobiles and the like because they have extremely excellent properties as shock absorbers. Many of the pad materials for instrument panels generally have a method in which a polyvinyl chloride skin or a polyurethane skin is set in a mold, and a semi-rigid polyurethane foam stock solution is injected and cured therein. Patent Document 1 describes a method for producing a crash pad made of a semi-rigid polyurethane foam having a short curing time, good moldability and few void defects.
JP 2001-354746 A

Crush pads for vehicle instrument panels or door trims for vehicles require raw materials with a short curing time and good formability, even when molded at a lower density than conventional methods, from the viewpoint of weight reduction and waste reduction. Yes. However, when the density of the molded product is further reduced by the above production method, there is a problem that the void area becomes large and the moldability becomes insufficient.
An object of the present invention is to provide a method of manufacturing a crash pad and a door trim for a vehicle instrument panel having low density and low void defects.

  As a result of intensive studies, the present inventors have completed the present invention by using a polyol composition comprising a polyol having a specific structure and combining it with a specific isocyanate component.

That is, the present invention comprises a polymer polyol (A) and / or a polyol (B) obtained by polymerizing a vinyl monomer (b) in a polyol (a), wherein (a) and / or (B) A polyol composition for producing a semi-rigid polyurethane foam containing the following polyols (a1), (a2), and (a3); the above polyol composition, the following polyisocyanate component (C), a foaming agent (D) comprising water, a catalyst (E) and, if necessary, a semi-rigid polyurethane foam-forming composition comprising a foam stabilizer (F); the semi-rigid polyurethane foam-forming composition is injected into a crush pad mold or a door trim mold, Semi-rigid poly, which is cured to produce crash pads or door trims for vehicle instrumental panels A method for producing a foam foam; and a semi-rigid polyurethane foam obtained by the above production method, having a void defect area ratio of 1.25% or less, and a ratio of a portion where voids are generated on the skin side to the substrate side is 20 A crash pad or door trim of a vehicle instrument panel that is 80 to 0: 100.
Polyol (a1): The average number of functional groups is 2.8 to 3.5, the hydroxyl value is 20 to 50 (mgKOH / g), the content of terminal oxyethylene units is 5 to 25% by mass, and oxyethylene units The polyoxyethylene polyoxypropylene polyol whose total amount of is 8-30 mass%.
Polyol (a2): The average number of functional groups is 2 to 2.5, the hydroxyl value is 20 to 70 (mg KOH / g), the content of terminal oxyethylene units is 5 to 40% by mass, and the total of oxyethylene units A polyoxyethylene polyoxypropylene polyol having an amount of 8 to 50% by mass.
Polyol (a3): A polyol having an average number of functional groups of 2 to 4 and a hydroxyl value of 1010 to 1840 (mgKOH / g).
Polyisocyanate component (C): a polyisocyanate component comprising 50% by mass or more of diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate and / or a modified product thereof, and 0 to 50% by mass of another polyisocyanate.

  According to the method for producing a semi-rigid polyurethane foam using the polyol composition and the semi-rigid polyurethane foam-forming composition of the present invention, the instrument has a lower density and less void defects than those obtained by the conventional method. It is possible to produce crashpads and door trims for mentment panels. Therefore, the production speed can be increased, and the yield can be greatly increased, the productivity can be improved, the number of mold surfaces required for production can be reduced, and the amount of waste can be greatly reduced.

In the polyol composition of the present invention, the polymer (b) obtained by polymerizing the vinyl monomer (b) in the polyol (a) serving as a polymer dispersion medium with the polymer polyol obtained is the polymer (b). (A) and (B) are used in combination even if the polyol composition is composed only of the polymer polyol (A) dispersed in the polymer, or the polyol composition is composed only of the polyol (B) other than the polymer polyol. It may be a polyol composition. In these, combined use of (A) and (B) is preferable.
In the polyol (a) and / or (B), that is, the component constituting the polyol composition excluding the polymer (b), the polyol (a1), the polyol (a2), and the polyol ( a3).

  Polyols (a1) to (a3) are compounds having at least two hydroxyl groups. Examples of (a1) and (a2) include polyhydric alcohols, polyhydric phenols, amines, polycarboxylic acids, and phosphoric acids. And a compound having a structure in which an alkylene oxide having 2 to 8 or more carbon atoms (hereinafter abbreviated as AO) is added to a compound having at least two active hydrogens. Also good.

  Examples of the polyhydric alcohol include dihydric alcohols having 2 to 20 carbon atoms (aliphatic diols such as ethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6-hexanediol, neopentyl Alkylene glycols such as glycols; and alicyclic diols such as cycloalkylene glycols such as cyclohexanediol and cyclohexanedimethanol, trihydric alcohols having 3 to 20 carbon atoms (aliphatic triols such as glycerin, trimethylolpropane, Alkanetriols such as methylolethane and hexanetriol); 4 to 8 or more polyhydric alcohols having 5 to 20 carbon atoms (aliphatic polyols such as pentaerythritol, sorbitol, mannitol, sorbitan, jigs) Alkane polyols such as serine and dipentaerythritol and intramolecular or intermolecular dehydrates of these or alkanetriols; and sugars such as sucrose, glucose, mannose, fructose, and methylglucoside and their derivatives), and two or more of these The combined use etc. are mentioned.

  Polyhydric (2 to 8 or more) phenols include monocyclic polyphenols such as pyrogallol, hydroquinone and phloroglucin; bisphenols such as bisphenol A, bisphenol F, and bisphenol sulfone; condensates of phenol and formaldehyde (novolac) ); For example, polyphenols described in US Pat. No. 3,265,641; and combinations of two or more thereof.

Examples of amines include those having 2 to 8 or more active hydrogens; ammonia; aliphatic amines having 2 to 20 carbon atoms such as monoethanolamine, diethanolamine, triethanolamine, Isopropanolamine and aminoethylethanolamine), alkylamines having 1 to 20 carbon atoms (for example, n-butylamine and octylamine), alkylenediamines having 2 to 6 carbon atoms (for example, ethylenediamine, propylenediamine and hexamethylenediamine), carbon Examples thereof include polyalkylene polyamines having 4 to 20 carbon atoms (dialkylene triamines having 6 to 6 carbon atoms in the alkylene group to hexaalkylene heptamines such as diethylenetriamine and triethylenetetramine).
C6-C20 aromatic mono- or polyamines (for example, aniline, phenylenediamine, tolylenediamine, xylylenediamine, diethyltoluenediamine, methylenedianiline, and diphenyletherdiamine); C4-C20 alicyclic Amines (for example, isophorone diamine, cyclohexylene diamine, and dicyclohexyl methane diamine); heterocyclic amines having 4 to 20 carbon atoms (for example, those described in piperazine, aminoethylpiperazine, and Japanese Patent Publication No. 55-21044), and these 2 The combined use etc. of a seed or more is mentioned.

Examples of the polycarboxylic acid include aliphatic polycarboxylic acids having 4 to 18 carbon atoms (succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, etc.), and aromatic polycarboxylic acids having 8 to 18 carbon atoms (phthalic acid, Terephthalic acid, isophthalic acid, trimellitic acid, etc.), and mixtures of two or more thereof.
Two or more of these active hydrogen-containing compounds may be used in combination. Of these, polyhydric alcohols are preferred.

In (a1) and (a2), AO added to the active hydrogen-containing compound is ethylene oxide (hereinafter abbreviated as EO) and propylene oxide (hereinafter abbreviated as PO). In both (a1) and (a2), AO is preferably composed only of these, but 10% by mass in AO (hereinafter, unless otherwise specified,% means mass%) or less (especially 5% or less). ) May be an adduct in which other AO is used in combination. Other AOs are preferably those having 4 to 8 carbon atoms, such as 1,2-, 1,3-, 1,4-, or 2,3-butylene oxide, and styrene oxide. It may be used. When two or more kinds of AO are used in combination, either block addition, random addition, or combination thereof may be used.
As a catalyst used at the time of AO addition, in addition to a commonly used alkali catalyst (KOH, CsOH, etc.), a catalyst described in JP-A No. 2000-344881 [Tris (pentafluorophenyl) borane, etc.], JP-A No. 11-120300 You may use the catalyst (magnesium perchlorate etc.) described in the gazette.

Specific examples of the polyols (a1) and (a2) include those obtained by adding PO and EO to the active hydrogen-containing compound in the following manner, and esterified products of these adducts with polycarboxylic acid or phosphoric acid, etc. Is mentioned.
[1] Blocks added in the order of PO-EO (chipd).
[2] A block added in the order of PO-EO-PO-EO (balanced).
[3] A block added in the order of EO-PO-EO.
[4] A block added in the order of PO-EO-PO (active secondary).
[5] A random adduct in which PO and EO are mixed and added.
[6] Random or block additions in the order described in JP-A-57-209920.
[7] Random or block added in the order described in JP-A-53-13700.

Examples of the polyol (a1) include an AO adduct composed of PO and EO of the above active hydrogen-containing compound, and two or more kinds may be used in combination. Two or more kinds of active hydrogen-containing compounds may be used in combination, preferably a trivalent to tetravalent polyhydric alcohol, more preferably a trivalent polyhydric alcohol.
The average number of functional groups per molecule of (a1) is 2.8 to 3.5. The lower limit is preferably 2.9, and the upper limit is preferably 3.2, more preferably 3.1. Even if the number of functional groups outside this range is included, it is an AO adduct of two or more active hydrogen-containing compounds as long as the average number of functional groups is within the above range (the average functionality of the following polyols). The same applies to the radix). Here, the average number of functional groups is obtained by regarding the theoretical value calculated from the average number of functional groups of the raw material as the number of functional groups. However, the number of functional groups in (a1) is preferably 2 to 4 (particularly 3).
The hydroxyl value is 20 to 50 (mg KOH / g, and the following hydroxyl values are the same). The lower limit is preferably 25, more preferably 30, and the upper limit is preferably 40, more preferably 35.
As an addition form of PO and EO, EO is added to the terminal and, if necessary, inside, and the total amount of oxyethylene units (hereinafter abbreviated as EO units) is 8 to 30%. The lower limit is preferably 10%, more preferably 12%, and the upper limit is preferably 20%, more preferably 16%. The content of terminal EO units is 5 to 25%. The lower limit is preferably 10%, more preferably 12%, and the upper limit is preferably 20%, more preferably 16%. The content of internal EO units is preferably 5% or less, more preferably 4% or less, and particularly preferably 0%.
When the average functional group number of (a1) is less than 2.8, the foam curing time is prolonged and the final hardness is lowered, so that the practicality is lowered, and when it exceeds 3.5, the elongation physical properties are lowered. When the hydroxyl value is less than 20, the foam curing time is prolonged and the final hardness is lowered, so that the practicality is lowered, and when it exceeds 50, the elongation property is lowered. If the total amount of EO units is less than 8% or the content of terminal EO units is less than 5%, the curing time of the foam becomes long, and the total amount of EO units exceeds 30%, or the content of terminal EO units. If it exceeds 25%, the curing time of the foam is too fast and the liquid flow of the foam becomes poor.

Examples of the polyol (a2) include an AO adduct composed of PO and EO of the above active hydrogen-containing compound, and two or more kinds may be used in combination. Two or more kinds of active hydrogen-containing compounds may be used in combination, and a divalent polyhydric alcohol is preferable, and a divalent polyhydric alcohol is more preferable.
The average number of functional groups per molecule of (a2) is 2 to 2.5. The upper limit is preferably 2.2. The hydroxyl value is 20-70. The lower limit is preferably 30, more preferably 40, and the upper limit is preferably 60, more preferably 50. As an addition form of PO and EO, EO is added to the terminal and, if necessary, inside, and the total amount of EO units is 8 to 50%. The lower limit is preferably 15%, more preferably 20%, and the upper limit is preferably 40%, more preferably 30%. The content of terminal EO units is 5 to 40%. The lower limit is preferably 15%, more preferably 20%, and the upper limit is preferably 35%, more preferably 27%. The content of internal EO units is preferably 5% or less, more preferably 4% or less, and particularly preferably 0%.
When the average functional group number of (a2) is less than 2, the foam curing time becomes long and the final hardness is lowered, so that the practicality is lowered, and when it exceeds 2.5, the elongation physical properties are lowered. When the hydroxyl value is less than 20, the void area increases, and when it exceeds 70, the elongation property is lowered. If the total amount of EO units is less than 8% or the content of terminal EO units is less than 5%, the curing time of the foam becomes long, and the total amount of EO units exceeds 50%, or the content of terminal EO units. If it exceeds 40%, the curing time of the foam is too fast and the liquid flow of the foam becomes poor.

Examples of the polyol (a3) include polyhydric alcohols. As polyhydric alcohol, the thing similar to the thing in said (a1) and (a2) is mentioned, You may use 2 or more types together.
The average number of functional groups per molecule of (a3) is 2-4. The upper limit is preferably 3, more preferably 2.5. The hydroxyl value is from 1010 to 1840. The lower limit is preferably 1300, more preferably 1400, and the upper limit is preferably 1700, more preferably 1500.
When the average functional group number of (a3) is less than 2, the foam curing time becomes long and the final hardness also decreases, so the practicality is lowered, and when it exceeds 4, the foam curing time is too fast and the liquid flow of the foam becomes worse. The stretch physical properties of the foam are reduced. If the hydroxyl value is less than 1010, the void area at low density increases, and if it exceeds 1840, the elongation physical properties decrease.

  The polymer polyol (A) in the present invention can be produced by polymerizing the vinyl monomer (b) by an ordinary method in the polyol (a). For example, the vinyl monomer (b) was polymerized in the presence of a radical polymerization initiator in at least one polyol selected from (a1), (a2) and (a3) shown above (b) ) In which the polymer is stably dispersed. Specific examples of the polymerization method include those described in US Pat. No. 3,383,351, Japanese Examined Patent Publication No. 39-25737, and the like.

  As the radical polymerization initiator, those that generate a free radical to initiate polymerization can be used, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile). ), Azo compounds such as 2,2′-azobis (2-methylbutyronitrile); organic peroxides such as dibenzoyl peroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide and persuccinic acid; Examples thereof include inorganic peroxides such as persulfate and perborate. In addition, these can use 2 or more types together.

As (b), aromatic vinyl monomer (b1), unsaturated nitriles (b2), (meth) acrylic acid esters (b3), other vinyl monomers (b4), and these two types The above mixture is mentioned.
Examples of (b1) include styrene, α-methylstyrene, hydroxystyrene, chlorostyrene, and the like.
Examples of (b2) include acrylonitrile and methacrylonitrile.
(B3) is composed of C, H and O atoms, for example, (meth) acrylic acid alkyl esters (alkyl group having 1 to 24 carbon atoms) [for example, methyl (meth) acrylate, butyl ( (Meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, eicosyl (meth) acrylate, docosyl (meth) acrylate], hydroxyalkyl (2 to 5 carbon atoms) (meth) acrylate [for example , Hydroxyethyl (meth) acrylate], and hydroxypolyoxyalkylene mono (meth) acrylates [for example, an alkylene group having 2 to 4 carbon atoms and a polyoxyalkylene chain having a number average molecular weight of 200 to 1000].

(B4) includes ethylenically unsaturated carboxylic acid and derivatives thereof, specifically (meth) acrylic acid, (meth) acrylamide, etc .; aliphatic or alicyclic hydrocarbon monomers, specifically alkene ( Ethylene, propylene, norbornene, etc.), alkadienes (butadiene, etc.); fluorine-based vinyl monomers, specifically fluorine-containing (meth) acrylates (perfluorooctylethyl methacrylate, perfluorooctylethyl acrylate, etc.), etc .; chlorine Vinyl-based monomers, specifically vinylidene chloride, etc .; nitrogen-containing vinyl monomers other than those mentioned above, specifically nitrogen-containing (meth) acrylates (diaminoethyl methacrylate, morpholinoethyl methacrylate, etc.); and vinyl-modified silicones Etc.
Preferred among these (b) are (b1) and (b2), particularly styrene and / or acrylonitrile.

The weight ratio of (b1), (b2), (b3) and (b4) in the vinyl monomer (b) can be changed according to the required physical properties of the polyurethane and is not particularly limited. An example is as follows.
(B1) and / or (b2) is preferably 50 to 100%, more preferably 80 to 100%. The weight ratio of (b1) and (b2) is not particularly limited, but is preferably 0/100 to 80/20. (B3) is preferably 0 to 50%, more preferably 0 to 20%. (B4) is preferably 0 to 10%, more preferably 0 to 5%.
Moreover, the strength of the polymer is further improved by using a small amount (preferably 0.05 to 1%) of a bifunctional or higher (preferably 2 to 8 functional) polyfunctional vinyl monomer (b5) in (b). Can be made. Examples of (b5) include divinylbenzene, ethylene di (meth) acrylate, polyalkylene (alkylene group having 2 to 8 carbon atoms, degree of polymerization: 2 to 10) glycol di (meth) acrylate, pentaerythritol triallyl ether, And methylolpropane tri (meth) acrylate.

  The content of the polymer (b) in the polymer polyol (A) is preferably 10 to 50%, more preferably 15% and the upper limit is 40%. When the content of the polymer is 10% or more, sufficient foam hardness can be exhibited, and when it is 50% or less, the viscosity of the polymer polyol becomes low and handling is easy.

  In the present invention, the polyol composition may contain other polyol or active hydrogen component (a4) in addition to the polyols (a1) to (a3). Examples of (a4) include polyether polyols, polyester polyols other than (a1) to (a3), various polyols or monools other than those described above, polyhydric alcohols, amines, and mixtures thereof.

Examples of polyether polyols other than (a1) to (a3) are the AO adducts of the active hydrogen-containing compound, and include those other than (a1) to (a3).
Examples of the polyester polyol include the above-mentioned polyhydric alcohols (in particular, dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol; Polyether polyols (particularly diols); or mixtures thereof with trihydric or higher polyhydric alcohols such as glycerin and trimethylolpropane; and the above polycarboxylic acids or ester-forming derivatives thereof (acid anhydrides, lower alkyls). (Alkyl group carbon number: 1-4) ester, etc.] (for example, adipic acid, sebacic acid, maleic anhydride, phthalic anhydride, dimethyl terephthalate), or a condensation reaction product of the carboxylic anhydride and AO; AO (EO, PO, etc.) adducts Polylactone polyols, such as those obtained by ring-opening polymerization of lactones (e.g., ε-caprolactone) using the polyhydric alcohol as an initiator; polycarbonate polyols, such as a reaction product of the polyhydric alcohol and alkylene carbonate; It is done.

Various polyols or monools include polydiene polyols such as polybutadiene polyol and hydrogenated products thereof; acrylic polyols, hydroxyl groups described in JP-A-58-57413 and JP-A-58-57414 Vinyl polymers; natural fat-based polyols such as castor oil; modified natural fat-based polyols such as castor oil-modified products (for example, polyhydric alcohol transesterification products and hydrogenated products); described in International Publication No. WO 98/44016 Terminal-radically polymerizable functional group-containing active hydrogen compounds (including monools); modified polyols obtained by jumping polyether polyols with alkylene dihalides such as methylene dihalide; OH-terminated prepolymers of polyether polyols; Can be mentioned.
Examples of the polyhydric alcohol and amine include those described above.

In the present invention, based on the total mass of (a) and (B), (a1) is 50 to 99%, (a2) is 0.9 to 45%, and (a3) is 0.1 to 5%. Is preferred. The lower limit of (a1) is preferably 65%, more preferably 70%, and the upper limit is preferably 89%, more preferably 85%. The lower limit of (a2) is preferably 10%, more preferably 14%, and the upper limit is preferably 32%, more preferably 27%. The lower limit of (a3) is preferably 1%, more preferably 1.5%, and the upper limit is preferably 3%, more preferably 2.5%.
The amount of the other polyol or active hydrogen component (a4) is preferably 5% or less, more preferably 1% or less.
When (a1) is 50% or more, the foam hardness shows a good value, and when it is 99% or less, the elongation property shows a good value. When (a2) is 0.9% or more, the liquid flowability of the urethane foam stock solution is good, and when it is 45% or less, the foam hardness shows a good value. When (a3) is 0.1% or more, the fluidity of the urethane foam stock solution is good and the void area is reduced, and when it is 5% or less, good curing properties are exhibited.

  In the present invention, the content of the polymer in the polyol composition is preferably 20% or less. The upper limit is preferably 15%, more preferably 10%, and the lower limit is preferably 1%, more preferably 3%. If it is 20% or less, the liquid flowability of the foam is not impaired, and the void area shows a good value.

As the polyisocyanate component (C) in the present invention, 50% or more of diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate and / or a modified product thereof (MDI type) is used for reasons such as improvement of productivity and improvement of working environment. And those consisting of 0 to 50% of other polyisocyanates are used. The content of MDI isocyanate is preferably 60% or more, and more preferably 80% or more. The content of other polyisocyanates is preferably 40% or less, more preferably 20% or less.
Examples of the modified product include urethane group, carbodiimide group, allophanate group, urea group, burette group, isocyanurate group, or oxazolidone group-containing modified product.

  As other polyisocyanates, all those usually used for polyurethane foams can be used, and aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and modified products thereof (for example, urethane groups, carbodiimide groups, allophanates). Group, urea group, burette group, isocyanurate group, or modified product containing oxazolidone group), and a mixture of two or more of these.

As aromatic polyisocyanate, C6-C16 aromatic diisocyanate, C6-C20 aromatic triisocyanate, and crude products of these isocyanates (excluding carbon in NCO group; the following isocyanate is also the same), etc. Is mentioned. Specific examples include 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate (TDI), crude TDI, naphthylene-1,5-diisocyanate, triphenylmethane-4, 4 ′, 4 ″ -triisocyanate and the like.
Examples of the aliphatic polyisocyanate include aliphatic diisocyanates having 6 to 10 carbon atoms. Specific examples include 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and the like.

Examples of the alicyclic polyisocyanate include alicyclic diisocyanates having 6 to 16 carbon atoms. Specific examples include isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and norbornane diisocyanate.
Examples of the araliphatic polyisocyanate include araliphatic diisocyanates having 8 to 12 carbon atoms. Specific examples include xylylene diisocyanate, α, α, α ′, α′-tetramethylxylylene diisocyanate, and the like.
Specific examples of the modified polyisocyanate include sucrose-modified TDI and castor oil-modified TDI.
Of these, preferred are aromatic polyisocyanates, and more preferred are TDI and crude TDI, particularly TDI.

  The MDI isocyanate includes 25 to 90% of diphenylmethane diisocyanate and / or polymethylene polyphenylene polyisocyanate, and 10 to 75% of a modified product of diphenylmethane diisocyanate and / or polymethylene polyphenylene polyisocyanate. The group content is preferably 18.8 to 32.2%. The lower limit is preferably 25%, more preferably 28% or more.

As the foaming agent (D) in the present invention, water is used as an essential component. If necessary, other blowing agents may be used together with water.
The usage-amount of water is 1-4 parts with respect to 100 mass parts of polyol compositions (henceforth abbreviated as a part only). The lower limit is preferably 1.5 parts, more preferably 1.9 parts, and the upper limit is preferably 3.5 parts, more preferably 2.8 parts.
In addition, hydrogen atom-containing halogenated hydrocarbons, low boiling point hydrocarbons, liquefied carbon dioxide, etc. are used as necessary.

Specific examples of hydrogen atom-containing halogenated hydrocarbon-based blowing agents include those of the HCFC (hydrochlorofluorocarbon) type (for example, HCFC-123, HCFC-141b, HCFC-22, and HCFC-142b); those of the HFC (hydrofluorocarbon) type (For example, HFC-134a, HFC-152a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, and HFC-365mfc).
Among these, HCFC-141b, HFC-134a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, and HFC-365mfc and mixtures of two or more thereof are preferred.
The amount of hydrogen atom-containing halogenated hydrocarbon used is preferably 50 parts or less, more preferably 5 to 45 parts, per 100 parts of the polyol composition.

The low boiling point hydrocarbon is usually a hydrocarbon having a boiling point of −5 to 70 ° C., and specific examples thereof include butane, pentane, cyclopentane, and mixtures thereof.
The amount of low boiling point hydrocarbon used is preferably 30 parts or less, more preferably 25 parts or less per 100 parts of the polyol composition.
The amount of liquefied carbon dioxide used is preferably 30 parts or less and more preferably 25 parts or less per 100 parts of the polyol composition.

As the catalyst (E) in the present invention, all usual catalysts for promoting the urethanization reaction can be used. Examples include triethylenediamine, triethylamine, bis (N, N-dimethylamino-2-ethyl) ether, N , N, N ', N'-tetramethylhexamethylenediamine, triethanolamine, N, N-dimethylaminopropyldipropanolamine and other tertiary amines and carboxylates thereof; potassium acetate, potassium octylate, stanas octo And organic metal compounds such as carboxylic acid metal salts such as dibutyltin dilaurate.
The amount (pure) used of (E) is preferably 0.05 to 4 parts, more preferably 0.1 to 3 parts, relative to 100 parts of the polyol composition.

  As the foam stabilizer (F) in the present invention, all those used in the production of ordinary polyurethane foams can be used. For example, a dimethylsiloxane foam stabilizer [for example, “SRX manufactured by Toledo Corning Silicone Co., Ltd.” -253 ", etc.], polyether-modified dimethylsiloxane foam stabilizers (for example," L-5309 "," SZ-1311 "manufactured by Nippon Unicar Co., Ltd.," SF-2972 "manufactured by Toledo Corning Silicone Co., Ltd.) "," SRX-274C "etc.] and the like. The amount of (F) used is preferably 3 parts or less, more preferably 2 parts or less, with respect to 100 parts of the polyol composition.

  In the semi-rigid polyurethane foam-forming composition of the present invention, if necessary, other auxiliary component (G) as described below may be used and reacted in the presence thereof. Colorants (dyes, pigments), flame retardants (phosphates, halogenated phosphates, etc.), anti-aging agents (triazoles, benzophenones), antioxidants (hindered phenols, hindered amines, etc.), Known auxiliary components such as an adhesive (modified caprolactone polyol, etc.) can be mentioned. With respect to the amount of these auxiliary components (G) used relative to 100 parts of the polyol composition, the colorant is preferably 1 part or less. The flame retardant is preferably 5 parts or less, more preferably 2 parts or less. The anti-aging agent is preferably 1 part or less, more preferably 0.5 part or less. The antioxidant is preferably 1 part or less, more preferably 0.01 part to 0.5 part. The adhesive is preferably 5 parts or less, more preferably 0.5 to 3 parts. Further, the total amount of (G) used is preferably 10 parts or less, more preferably 0.01 to 5 parts.

  In the production method of the present invention, the isocyanate index [(NCO group / active hydrogen atom-containing group equivalent ratio × 100) (index) in the production of polyurethane is preferably 65 to 130, more preferably 70 to 120, particularly. Preferably it is 95-115. When the isocyanate index is 65 or more, the foam hardness is good, and when it is 125 or less, the curing time of the foam can be shortened.

An example of a method for producing a semi-rigid polyurethane foam using the semi-rigid polyurethane foam-forming composition of the present invention is as follows.
First, a predetermined amount of the polyol composition of the present invention, the foaming agent (D), the catalyst (E), and, if necessary, the foam stabilizer (F) and / or other auxiliary component (G) are mixed. Next, using a polyurethane foaming machine (low pressure or high pressure foaming machine, preferably a high pressure foaming machine) or a stirrer, this mixture (hereinafter referred to as M component) and a component comprising the polyisocyanate component (C) (hereinafter referred to as N component) And mix rapidly. The obtained mixture is poured into a crush pad mold or a door trim mold (preferably 25 to 50 ° C.) in which a skin and a base material are set on each side, and demolded after a predetermined time. A semi-rigid polyurethane foam having a uniform density distribution is obtained. Additives, auxiliaries, and the like can be mixed with the N component and used. The filling rate [(density at the time of mold foaming / density at the time of free foaming) × 100] at the time of pouring is preferably 100 to 400%, particularly preferably 150 to 350%.

As the above-mentioned skin, for example, polyvinyl chloride or polyurethane is used. The thickness of the epidermis is preferably 0.2-2 mm.
Examples of the substrate include polypropylene and glass fiber reinforced acrylonitrile / styrene copolymer resin. The thickness of the substrate is preferably 2 to 4 mm.

The apparent density (g / cm ³ ) of the foam obtained using the semi-rigid polyurethane foam-forming composition of the present invention is preferably 0.05 to 0.4, more preferably 0.14 to 0.2. is there. The C hardness of the foam is preferably 30 to 100, more preferably 40 to 80.

  When the semi-rigid polyurethane foam of the present invention comprising the polyol composition of the present invention is used to produce a semi-rigid polyurethane foam by pouring it into a mold for crash pad or door trim. In addition, the cream time can be easily set to 5 seconds or longer and the curing time can be set to 60 seconds or less by appropriately adjusting the amount of the catalyst and the isocyanate index within the range usually used.

The above cream time refers to the reaction between the foaming agent (water) and the isocyanate when the liquid temperature of the raw material (polyurethane foam-forming composition) immediately before the reaction is 25 ° C. and the mold temperature is 40 ° C. Thus, the foaming reaction starts and the foaming starts.
When using a closed injection type crush pad mold, when the cream time is 5 seconds or more, good liquid flowability is exhibited during molding, and the void area of the urethane foam exhibits a good value.

  The curing time means the time from the start of the reaction mixture injection to the start of mold opening when injected into the mold under the same conditions as the cream time. When the mold is opened with insufficient curing, the crash pad is deformed.

  When the semi-rigid polyurethane foam-forming composition of the present invention is used to mold a semi-rigid polyurethane foam by the method of the present invention, the void defect area ratio is 1.25% or less and the skin side of the part where voids are generated It is possible to easily obtain a crash pad of a vehicle instrument panel in which the ratio on the base material side (hereinafter referred to as void defect rate) is 20:80 to 0: 100.

  The void in the present invention means a circular bubble having a diameter of 2 mm or more or an elliptical shape close to a circle, which is generated when air accumulates on the urethane foam surface and / or inside when a crash pad of a vehicle instrument panel is molded. To do. The diameter of the void is usually 2 to 20 mm.

The void defect area ratio is a ratio of the total area of voids having an average diameter of 2 mm or more to the surface area of the semi-rigid polyurethane foam on the skin side after peeling the skin of the crash pad,
(I) The major axis and minor axis of the void are measured in mm with a metal ruler having a minimum scale of 1 mm.
(Ii) One void area is calculated by major axis × minor axis × circumference (unit: cm, significant number: two digits after the decimal point).
(Iii) The total void area per surface area 2000 cm ² on the skin side of the foam is obtained, and the ratio (%) to the foam surface area is obtained.
It is required by the method.

Moreover, a void ratio is calculated | required with the following method.
(I) The molded product is cut in a direction perpendicular to the skin, and a line is drawn at the center of the foam layer on the cut surface (intermediate point between the base material and the skin).
(Ii) The sum of the void areas on the skin side and the base material side is determined by the above method.
(Iii) The measurement is performed a plurality of times so that the total cross-sectional area of the measured foam is 1000 cm ² or more, and the ratio of the skin side to the substrate side is obtained from the ratio of the void defect area ratio on each side.

  When the void defect area ratio exceeds 1.25%, the skin of the instrument panel product is dented, or swelling occurs in a high-temperature environment, resulting in an appearance defect. On the other hand, if the void ratio on the skin side exceeds 20%, the skin of the instrument panel is dented, or swelling occurs in a high temperature environment, resulting in poor appearance.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited by this. In addition, since the content of the internal EO unit of the following polyol is all 0%, it abbreviate | omits. Therefore, the total amount of EO units is the same as the content of terminal EO units.

The polyurethane foam raw materials in Examples and Comparative Examples are as follows.
(1) Polyol a1-1: A chipped polyol having a number average molecular weight of 5000, a hydroxyl value of 33.7, and a terminal EO unit content of 14%, obtained by adding PO to glycerol and then adding EO.
(2) Polyol a2-1: A chipped polyol having a number average molecular weight of 2440, a hydroxyl value of 46.0, and a terminal EO unit content of 25%, obtained by adding PO to propylene glycol and then adding EO.
(3) Polyol a3-1: Propylene glycol (hydroxyl value 1474).
(4) Polyol x-1: A chipped polyol having a number average molecular weight of 8000, a hydroxyl value of 28.1, and a terminal EO unit content of 14%, obtained by adding PO to pentaerythritol and then adding EO.
(5) Polyol x-2: A chipped polyol having a number average molecular weight of 600, a hydroxyl value of 280, and a terminal EO unit content of 10%, obtained by adding PO to glycerin and then adding EO.
(6) Polymer polyol A-1: Polymer polyol obtained by polymerizing acrylonitrile in polyol a1-1 (polymer content 20%).
(7) Polymer polyol X-1: A polymer polyol obtained by polymerizing acrylonitrile and styrene in a polyol x-1 at a mass ratio of 2: 1 (polymer content 30%).

(8) Catalyst E-1: Triethanolamine.
(9) Catalyst E-2: Tertiary amine catalyst [Kao Riser P-200, manufactured by Kao Corporation]
(10) Catalyst E-3: 70% dipropylene glycol solution of bis (N, N-dimethylamino-2-ethyl) ether [“TOYOCAT-ET” manufactured by Tosoh Corporation]
(11) Catalyst E-4: Triethylamine (12) Catalyst E-5: N, N-dimethylaminopropyldipropanolamine [San Apro Co., Ltd. “UCAT2024”]
(13) Adhesive G-1: Modified polycaprolactone polyol [“Ester D” manufactured by Sanyo Chemical Industries, Ltd.]

(14) Isocyanate C-1: Modified MDI [Nippon Polyurethane Co., Ltd. “Millionate MR-200”]
(15) Isocyanate C-2: Modified MDI [“CEI-264” manufactured by Nippon Polyurethane Co., Ltd.]

Examples 1-6 and Comparative Examples 1-5
Using a high-pressure foaming machine (Mini-RIM machine manufactured by PEC), the M component and N component in the number of parts shown in Table 1 were mixed and injected into a 200 mm × 1000 mm × 10 mm closed injection type metal mold. In the mold, a polyvinyl chloride skin having a thickness of 1 mm and a polypropylene substrate having a thickness of 3 mm were set on each side in advance. Tables 1 and 2 show the molding conditions, the physical property values of the obtained foams, and the measurement results of the moldability.

The evaluation methods of foam physical properties in Tables 1 and 2 are as follows.
Apparent density (g / cm ³ ): Tensile strength (kgf / cm ² ) according to JIS K6400 (1997): Tear strength (kgf / cm) according to JIS K6400 (1997): Elongation according to JIS K6400 (1997) (%): C hardness according to JIS K6400 (1997): Measured by Shore C hardness meter Void defect area ratio: According to the method described in paragraph 0049.
Void ratio: According to the method described in paragraph 0050. However, cutting the form
Measurements were performed at 1 cm intervals in the length (1000 mm) direction.

  Semi-rigid polyurethane foam obtained by using the polyol composition and semi-rigid polyurethane foam-forming composition of the present invention has lower density and less void defects than conventional ones. Useful as a crash pad or door trim. Moreover, since a semi-rigid polyurethane foam having a good appearance can be obtained, in addition to these uses, it can also be suitably used as various automotive interior members such as headrests and armrests.

Claims (6)

A polymer polyol (A) and / or polyol (B) obtained by polymerizing the vinyl monomer (b) in the polyol (a), and the following polyol (a1) in (a) and / or (B) A polyol composition for producing a semi-rigid polyurethane foam, comprising (a2) and (a3).
Polyol (a1): The average number of functional groups is 2.8 to 3.5, the hydroxyl value is 20 to 50 (mgKOH / g), the content of terminal oxyethylene units is 5 to 25% by mass, and oxyethylene units The polyoxyethylene polyoxypropylene polyol whose total amount of is 8-30 mass%.
Polyol (a2): The average number of functional groups is 2 to 2.5, the hydroxyl value is 20 to 70 (mg KOH / g), the content of terminal oxyethylene units is 5 to 40% by mass, and the total of oxyethylene units A polyoxyethylene polyoxypropylene polyol having an amount of 8 to 50% by mass.
Polyol (a3): A polyol having an average number of functional groups of 2 to 4 and a hydroxyl value of 1010 to 1840 (mgKOH / g). The content (% by mass) of (a1), (a2), and (a3) based on the total mass of (a) and (B) is (a1) :( a2) :( a3) = (50 to 99) :( The polyol composition for producing a semi-rigid polyurethane foam according to claim 1, which is 0.9 to 45): (0.1 to 5). Formability of semi-rigid polyurethane foam comprising the polyol composition according to claim 1 or 2, the following polyisocyanate component (C), a foaming agent (D) comprising water, a catalyst (E), and optionally a foam stabilizer (F). Composition.
Polyisocyanate component (C): a polyisocyanate component comprising 50% by mass or more of diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate and / or a modified product thereof, and 0 to 50% by mass of another polyisocyanate. The semi-rigid polyurethane foam according to claim 3, which has a cream time of 5 seconds or longer and a curing time of 60 seconds or less when foamed and cured in a mold for crash pad at 40 ° C at a liquid temperature of 25 ° C. Formable composition. A semi-rigid polyurethane foam-forming composition according to claim 3 or 4 is injected into a crash pad mold or door trim mold, and foamed and cured to produce a crash pad or door trim for a vehicle instrument panel. A method for producing a characteristic semi-rigid polyurethane foam. It consists of a semi-rigid polyurethane foam obtained by the manufacturing method according to claim 5, wherein the void defect area ratio is 1.25% or less, and the ratio of the skin side to the substrate side of the part where voids are generated is 20:80 to Crash pad or door trim of a vehicle instrument panel that is 0: 100.