JP2700519B2 - Manufacturing method of flexible polyurethane foam and thermoforming body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a thermoformed flexible polyurethane foam and a method for producing a thermoformed flexible polyurethane foam. More specifically, door trim for automobiles, armrests, headrests, seat cushions,
Method for producing thermoformed flexible polyurethane foam useful for interior materials such as instrument panels, console boxes, sun visors, sound-insulating materials such as dash silencers, undercarpets, and clothing pads, and thermoformed articles obtained from the obtained flexible polyurethane foam Related to the production method.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a flexible polyurethane foam used as an interior material or a soundproofing material of an automobile or the like, there is known a molding foam molding method in which a reaction mixture of a flexible polyurethane foam is directly poured into a mold and foamed. . For clothing pads, there is widely used a method of cutting a general-purpose soft polyurethane slab stock foam into an appropriate thickness and thermoforming this with a press for heat molding.

[0003]

However, the above method has the following problems. In the mold foaming molding method, the resulting molded article has a skin layer peculiar to mold foaming on its surface, so that the surface has reduced air permeability and is easily stuffy, resulting in inferior comfort or soundproof performance. It has the disadvantage that molding defects are likely to occur in the shape having the mold; or the cost required for the mold equipment and the mold temperature control equipment is high. General-purpose flexible polyurethane slabstock foams used for clothing pads have insufficient thermoformability, require long-term pressing at high temperatures, and cause discoloration or thermal deterioration of the foams.

[0004]

The present inventors have conducted intensive studies to solve these problems and found that a thermoformed flexible polyurethane foam excellent in comfort, soundproofing performance, moldability, thermoformability and the like was obtained. The present inventors have found a production method and a method for producing a thermoformed article from the obtained flexible polyurethane foam, and have reached the present invention.

That is, the present invention relates to an active hydrogen-containing compound (a)
And the organic polyisocyanate (b) in the presence of a catalyst (c), a blowing agent (d) and, if necessary, other additives (e) to produce a thermoformable flexible polyurethane foam, a) has an average number of functional groups of 2 to 6,
An active hydrogen-containing compound having an average hydroxyl value of 20 to 200 (a
1) and at least one which blocks an isocyanate group
(A1): (a2) =
(99.5 to 80): a method of producing a thermoformable flexible polyurethane foam, which is a weight ratio of (0.5 to 20) and produced by a slab method; and thermoformability obtained by this method A method for producing a thermoformed flexible polyurethane foam, which comprises hot-pressing a flexible polyurethane foam.

In the present invention, the active hydrogen-containing compound (a) which is a component constituting the active hydrogen-containing compound (a)
Examples of 1) include alcohols, phenols,
Amines and the like, alkylene oxide adducts thereof, polyester polyols (hereinafter, these alkylene oxide adducts and / or polyester polyols are simply abbreviated as polyols) and polymer polyols obtained by polymerizing vinyl monomers in the polyols. No. Examples of the alcohols include monohydric alcohols [methanol, ethanol, n- and is-
o-propanol, butanol, 2-ethylhexanol, cyclohexanol, benzyl alcohol, etc.]; 2
Dihydric alcohols [ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol and the like]; and trihydric or higher alcohols [glycerin,
Trimethylolpropane, pentaerythritol, sorbitol, sucrose, etc.]. Examples of phenols include alkylphenols [phenol and nonylphenol and the like]. Examples of amines include ammonia; alkanolamines [mono-, di- and triethanolamine, isopropanolamine, aminoethylethanolamine, etc.]; alkylamines having 1 to 20 carbon atoms [butylamine, laurylamine, etc.]; 2-6 alkylenediamines [ethylenediamine,
Hexamethylenediamine, etc.]; polyalkylenepolyamines [diethylenetriamine, triethylenetetramine, etc.]; aromatic amines [aniline, phenylenediamine, diaminotoluene, xylylenediamine, methylenedianiline, diphenyletherdiamine, etc.]: alicyclic amines [Isophoronediamine, cyclohexylenediamine, etc.]; aminoethylpiperazine and JP-B-55-
Heterocyclic amines described in JP 21044A. Two or more of these active hydrogen-containing compounds can be used in combination.

As the alkylene oxide, ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), 1,2-, 1,4- and 2,
3-butylene oxide and the like, and a combination of two or more of these. Of these, preferred are PO and a combination of EO and PO, and the additional form in the case of combined use may be either block or random.

Examples of the polyester polyol include low-molecular-weight polyols (such as the above-mentioned dihydric alcohols and trihydric alcohols) and polycarboxylic acids (such as aliphatic polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, maleic acid and dimer acid). Condensed polyester polyols obtained by reacting with phthalic acid, terephthalic acid, trimellitic acid, etc.) and the above-mentioned alcohols and / or phenols with ε-caprolactone. Examples include polycaprolactone polyol and polycarbonate polyol (such as polyhexylene carbonate diol).

Examples of the polymer polyol include those obtained by polymerizing and stably dispersing a vinyl monomer such as acrylonitrile and styrene in at least one of the polyols exemplified above in the presence of a radical initiator. The content of the vinyl polymer in the polymer polyol is usually 50% or less.

Among the compounds exemplified as (a1) above, preferred are an alkylene oxide adduct of an alcohol, a polymer polyol obtained by polymerizing a vinyl monomer in the adduct, and a combination thereof. Those exemplified as (a1) may be used in combination of two or more kinds. The (a
The average number of functional groups of 1) is usually 2 to 6, preferably 2.5 to
4, and the average hydroxyl value is usually 20 to 200, preferably 20 to 100. Average functionality less than 2 and 6
If it exceeds 300, foaming stability, soundproofing properties and thermoformability are inferior. On the other hand, when the hydroxyl value exceeds 200, the obtained polyurethane foam becomes too hard, and the desired flexible polyurethane foam cannot be obtained.

In the present invention, the at least one compound (a2) for blocking an isocyanate group includes phenols (phenol, nonylphenol, cresol, 3,5-xylenol, carvacrol, thymol, naphthol, catechol, resorcinol) , Hydroquinone, etc.), bisphenols (such as bisphenol A), lactams (such as ε-caprolactam), oximes (such as MEK oxime), active methylene group-containing compounds (such as ethyl malonate and acetylacetone), and isocyanate group-reactive inorganics Compounds (sodium acid sulfite, hydrogen cyanide, boric acid, etc.). These may be used in combination of two or more.

Particularly preferred among those exemplified above as (a2) are bisphenol A, nonylphenol and ε-caprolactam.

In the present invention, the weight ratio of (a1) to (a2) is such that (a1) :( a2) is (99.5 to 8).
0): (0.5-20), preferably (99.5-9)
0): (0.5 to 10), more preferably (99 to 9)
5): (1 to 5). When the ratio of (a2) is less than 0.5, the thermoformability of the obtained foam is inferior.

As the organic polyisocyanate (b) used in the present invention, those generally used for polyurethane are used. Specific examples of (b) include aromatic polyisocyanates having 6 to 20 carbon atoms (excluding the number of carbon atoms in the NCO group) [2,4- and / or 2,6-tolylene diisocyanate (TDI), crude TDI , 2,4-
And / or 4,4'-diphenylmethane diisocyanate (MDI), crude MDI, polyaryl polyisocyanate (PAPI), etc.]; aliphatic isocyanates having 2 to 18 carbon atoms [hexamethylene diisocyanate, lysine diisocyanate, etc.]; 15 alicyclic polyisocyanates [isophorone diisocyanate, dicyclohexyl diisocyanate, etc.]; araliphatic polyisocyanates having 8 to 15 carbon atoms [xylylene diisocyanate, etc.]; Group, urea group, buret group, uretdione group, uretonimine group, isocyanurate group, oxazolidone group-containing modified product, etc.]; and other polyethers described in JP-A-61-76517. Isocyanate; and combinations of two or more of these. Preferred of these are TDI,
A mixture of TDI and crude MDI and 2,4- and / or 4,4'-MDI.

In the present invention, the catalyst (c) may be any of those usually used as a catalyst for foaming urethane. Examples of the catalyst include metal salts of carboxylic acids [sodium acetate, lead octylate, zinc octylate, cobalt naphthenate]. Alkoxides or phenoxides of alkali metals or alkaline earth metals [sodium methoxide, sodium phenoxide, etc.]; tertiary amines [triethylamine, triethylenediamine, N-methylmorpholine, dimethylaminomethylphenol, pyridine, etc.]; Ammonium salts [such as tetraethylhydroxyammonium]; imidazoles [such as imidazole and 2-ethyl-4-methylimidazole]; and organometallic compounds containing tin or antimony [such as tetraphenyltin and tributylantimony] And silicic acid stannate octoate]. Of these, tertiary amines and organometallic compounds containing tin or antimony are preferred.

In the present invention, examples of the blowing agent (d) include water and / or other blowing agents (such as trichloromonofluoromethane and methylene chloride).

In the present invention, other additives (e) used as necessary include surfactants (for example, SZ-1306, L-520, L-540 manufactured by Nippon Unicar, SH-190 manufactured by Toray Silicon, SRX-274C
Etc.), pigments, fillers, asphalt, flame retardants, solvents,
And thixotropic agents.

In the production method of the present invention, the amounts of (b) to (d) used per 100 parts by weight of (a) are as follows. The amount of (b) is such that the NCO index is usually 60 to 140, preferably 80 to 120. The amount of (c) is usually 0.01 to 3 parts, preferably 0.03 parts.
5 to 2 parts. The amount of (d) is an amount used for foaming a general urethane foam (for example, 1 to 5 parts of water, and 0 to 2 parts of another foaming agent).
5 parts).

[0019] The flexible polyurethane foam physical properties obtained in the present invention (original physical properties before thermoforming) are foam density is usually 10~500kg / ^{m 3.} The 25% compression hardness is usually ^{2 to} 60 kg / 314 cm ² , preferably 3 to 40 kg / 314 cm ² . The rebound resilience of the foam is usually 20-80%, preferably 30-70%. The compression set of the foam is usually 30% or less, preferably 15% or less. When the original properties of the foam are out of the above ranges, the foaming properties and thermoformability are poor, or a normal flexible polyurethane foam is not obtained.

In the present invention, the foaming method is not particularly limited. For example, a flexible polyurethane foam can be obtained by mixing and agitating a mixture of components other than (b) and (b) and foaming. At this time, components other than (b) may be further divided and used, and then mixed with (b). Further, (a2) may be mixed with (b) first, and then the remaining components may be mixed and stirred to foam.

In the present invention, the flexible polyurethane foam is manufactured by a slab system without requiring any special manufacturing equipment.

In the present invention, the thermoforming of the flexible polyurethane foam is carried out by heating and press molding with a conventional apparatus. Heating may be performed by microwaves other than the usual method. In the thermoforming, the foam may be heated to a predetermined temperature immediately before pressing, and then pressed with a room temperature or cooled press machine. preferable. The heating temperature is usually 100 to 210 ° C., preferably 150
~ 200 ° C. If the heating temperature is lower than 100 ° C., the thermoformability is poor. The pressurization is usually performed at 0.5 kg / cm ² or more. When the pressure is less than 0.5 kg / cm ² , the thermoformability is poor.

[0023]

The present invention will be described in more detail with reference to the following examples, which, however, are not intended to limit the scope of the present invention. In the following, “part” indicates “part by weight” and “%” indicates “% by weight”.

EXAMPLES 1 TO 6 AND COMPARATIVE EXAMPLES 1 AND 2 According to the foaming formulations shown in Tables 1 and 2, the foam was free-foamed in a paper box having an open top, and the obtained polyurethane foam was cut. Physical properties were measured. The thermoformability was determined by cutting a foam into 50 mm x 200 mm x 20 mm, and pressing it at a pressure of 50 kg / cm ² with a press machine having a breath surface of 170 ° C.
It was taken out after pressing for 2 seconds and its shape retention was evaluated. Tables 1 and 2 show the evaluation results.

(Foaming conditions) Paper box shape: 400 mm × 400 mm × 200 mm Mixing method: Stirring with a mixer at 3000 rpm Raw material temperature: 25 ± 2 ° C. Raw material usage: 300 g of (a1) Curing condition: Room temperature, 1 day

(Raw materials) Active hydrogen-containing compound (a1) a1-1: PO adduct of glycerin, molecular weight 3,000 a1-2: PO-EO adduct of glycerin, molecular weight 6,000 a1-3: a1 -2 polymer polyol, polymer component styrene / acrylonitrile = 5/5, polymer content 20% a1-4: diethanolamine-isocyanate group blocking compound (a2) a2-1: bisphenol A a2-2: nonylphenol a2-3: ε-caprolactam isocyanate (b) b-1: TDI-80 (mixture of 2,4-toluene diisocyanate / 2,6-toluene diisocyanate = 80/20) b-2: TDI-80 / crude MDI = 80/20 -Catalyst (c) 33LV: DABCO 33LV, that is, triethylene diamine 33% dipropylene glycol solution DMEA: dimethylaminoethanol T-9: Stanas octate ・ Blowing agent (d) Using water ・ Additive (e) L520: Silicone foam stabilizer L- manufactured by Nippon Unicar Co., Ltd. 520 274C: Silicone yarn foam stabilizer SRX-274C manufactured by Toray Silicone Co., Ltd.

(Method of measuring physical properties of foam) The physical properties of foam were measured in accordance with JIS K6401. The unit is as follows. Free foam density: kg
/ M ³ , 25% compression hardness: kg / 314 cm ² , compression set:%, rebound resilience:%

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

The thermoformed article from the flexible polyurethane foam obtained by the production method of the present invention is obtained by a method excellent in thermoformability. In addition, the slab foam is cut and thermoformed, and unlike a molded product, it does not have a skin layer, so it has excellent comfort and soundproofing, and is used for interior materials such as automobiles, aircraft, trains, and houses. Useful as soundproofing and clothing pads.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08G 101: 00) B29K 75:00 C08L 75:04

Claims (3)

(57) [Claims] An active hydrogen-containing compound (a) is reacted with an organic polyisocyanate (b) in the presence of a catalyst (c), a blowing agent (d) and, if necessary, other additives (e).
In the method for producing a thermoformable flexible polyurethane foam, (a) is an active hydrogen-containing compound (a1) having an average number of functional groups of 2 to 6 and an average hydroxyl value of 20 to 200, and at least one kind which blocks an isocyanate group. (A1): (a2) = (99.5−
80): (0.5 to 20) weight ratio , slab system
A method for producing a thermoformable flexible polyurethane foam, characterized by being produced by: 2. The method according to claim 1, wherein (a2) is at least one selected from bisphenol A, nonylphenol and ε-caprolactam. 3. A process according to claim 1 or 2, wherein
Hot press molding of thermoformable flexible polyurethane foam
Of a thermoformed flexible polyurethane foam
Manufacturing method.