JPH06329747A - Production of foamed polyurethane molding - Google Patents

Abstract

PURPOSE:To produce a foamed polyurethane molding being lightweight and uniform, having good heat resistance and reduced in dusting during cutting by using a specified polyol. CONSTITUTION:A polyol component (A) comprising an aromatic-ring-containing polyol (a) of a hydroxyl value of 200-400 represented by the formula and an aliphatic polyol (b) of a hydroxyl value of 250-500, an aromatic polyisocyanate component (B) and 1-8 pts.wt., per 100 pts.wt. component A, dehydrating agent (C) are subjected to a foaming reaction in the substantial absence of a blowing agent according to the mechanical froth process. In the formula, X is any one group selected from among H, CH3, Cl and Br; Y is any one group selected from among CH2, C(CH3)2, SO2, O and a single bond; A is a propylene group or an ethylene group; and m+n=0-13. The ratio between components (a) and (b) in component A is usually about 10:90 to 40:60. When 2-20 pts.wt. per 100 pts.wt. component A is added, the effect of weight reduction can be further enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a lightweight and uniform foamed polyurethane molded article which has no density distribution and is uniform. More specifically, the present invention relates to a method for producing a foamed polyurethane molded product suitable for a model material having a small amount of dust generated during cutting and having good heat resistance.

[0002]

2. Description of the Related Art Conventionally, there is a technique for producing a rigid polyurethane foam having a low density distribution by combining a high molecular weight polyol and a low molecular weight polyol and reducing the weight by a mechanical floss method (for example, JP-A-4- 356517).

[0003]

However, when the rigid polyurethane foam obtained here is cut as a model material, generation of dust is unavoidable. In recent years, work environment improvement has been emphasized, and demands for reducing generated dust have become stronger. As a means for suppressing the generation of dust during cutting, a method of lowering the crosslink density of the resin can be considered, but in that case, it is not suitable as a model material because it has poor heat resistance and softens when the temperature rises.

[0004]

Means for Solving the Problems The inventors of the present invention have made extensive studies on a foamed polyurethane molded product which produces a small amount of dust during cutting without lowering the heat resistance, and as a result, uses a specific polyol. As a result, they have found that the above problems can be solved, and have reached the present invention.

That is, the present invention provides a polyol component (A) comprising an aromatic ring-containing polyol (a) having a hydroxyl value of 200 to 400 represented by the following general formula and an aliphatic polyol (b) having a hydroxyl value of 250 to 500. And an aromatic polyisocyanate component (B) and 1 to 8 parts by weight of the dehydrating agent (C) per 100 parts by weight of the polyol component (A), and foamed by a mechanical froth method containing substantially no foaming agent. And a method for producing a foamed polyurethane molded article.

[0006]

[Chemical 2]

(Wherein X is a group of H, CH3, Cl or Br; -Y- is -CH2-, -C (CH3) 2-, -SO2
-, -O-, a single bond group; A is a propylene group or an ethylene group; and m + n is a number from 0 to 13. )

Examples of the aromatic ring-containing polyol (a) in the present invention include bisphenols, polyols obtained by adding alkylene oxide thereto, and mixtures of two or more thereof.

Specific examples of the above bisphenols include:
For example, bisphenol A [2,2'-bis (4-hydroxyphenyl) propane], bisphenol F [2,
2'-bis (4-hydroxyphenyl) methane], bisphenol S [2,2'-bis (4-hydroxyphenyl) sulfone], 2,2'-bis (4-hydroxyphenyl) ether, 4,4'- Dihydroxybiphenyl,
2,2'-bis (4-hydroxyphenyl) hexafluoropropane may be mentioned. Bisphenol A and bisphenol F are preferred.

The above bisphenols can be used as they are as the aromatic ring-containing polyol (a), but the alkylene oxide adducts thereof are more preferable. Examples of the alkylene oxide include propylene oxide (hereinafter abbreviated as PO) and ethylene oxide (hereinafter EO).
And a combination of these two (block and / or random addition). Preferred is
It is a combination of PO and PO / EO.

The hydroxyl value of the aromatic ring-containing polyol (a) used in the present invention is usually 200 to 400, preferably 250 to 350. When the hydroxyl value is less than 200, the heat resistance of the obtained polyurethane foam molded article is not sufficient, and when it exceeds 400, it tends to be hard and brittle.

Examples of the aliphatic polyol (b) in the present invention include alkylene oxide (for example, PO, EO and a combination of these two types) adduct of polyhydric alcohol. The polyhydric alcohol is an alcohol having 2 to 8 hydroxyl groups in one molecule, and examples thereof include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, glycerin, trimethylolpropane, pentaerythritol, and methyl. Examples include glycosides, diglycerin, sorbitol, glucose, and sucrose. Preferably, it has 2 to 4 hydroxyl groups, and is propylene glycol, glycerin, pentaerythritol, or methyl glycoside.

The hydroxyl value of the aliphatic polyol (b) is usually 200 to 500, preferably 250 to
It is 450. If the hydroxyl value is less than 200, the heat resistance of the obtained polyurethane foam molded article will be poor, and
If it exceeds 0, the amount of dust generated increases.

The weight ratio of the aromatic ring-containing polyol (a) to the aliphatic polyol (b) is 10/90 to 40/60, preferably 10/90 to 30/70.

When the ratio of the aromatic ring-containing polyol (a) is large, the obtained foamed polyurethane molded product has a strong stickiness and the machinability as a model material is deteriorated. On the other hand, when the ratio of the aliphatic polyol (b) is large, the obtained foamed polyurethane molded product becomes hard and brittle, and when used as a model material, much dust is generated during cutting.

As the polyol component (A) of the present invention, a polyol other than the above (a) and (b), for example, polybutadiene polyol, acrylic polyol, polymer polyol modified with ethylenically unsaturated monomer, and bisphenols. Other aromatic ring-containing polyols (for example, hydroquinones, condensates of phenolformaldehyde, aromatic ring-containing polyester polyols, and polyols obtained by adding alkylene oxide thereto; alkylene oxide adducts of aromatic amines), etc. You can use it together.

As the aromatic polyisocyanate (B) used in the present invention, those conventionally used for polyurethane can be used. Examples of such aromatic polyisocyanates include ordinary aromatic polyisocyanates and modified products thereof (for example, carbodiimide group,
Allophanate groups, urea groups, burette groups, isocyanurate groups, oxazolidone group-containing modified products, etc.), isocyanate group-terminated prepolymers and mixtures thereof.

Specific examples of such aromatic polyisocyanates include 1,3- and 1,4-phenylene diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate (TDI), crude TDI, Diphenylmethane-2,4'- and / or -4,4'-diisocyanate (MDI), polymethylene polyphenylisocyanate (crude MDI), naphthylene-1,5-diisocyanate, triphenylmethane-4,4 '. ，
4 ''-triisocyanate, carbodiimide modified MD
I, polyhydric alcohols such as sucrose, and isocyanate group-terminated prepolymers of TDI. Of these, preferred are TDI, crude TDI, MDI, and crude MDI.

The ratio of the polyol component (A) to the aromatic polyisocyanate (B) can be variously changed,
The equivalent ratio of the hydroxyl group of (A) to the isocyanate group of (B) is usually 1.0: 0.5 to 1.0: 1.5, preferably 1.0: 0.9 to 1.0: 1. It is 2. Further, the equivalent ratio of the hydroxyl group and the isocyanate group is 1.0: 1.
When the ratio is 5 to 1.0: 50, a polyisocyanurate foam can be produced.

As the dehydrating agent (C) of the present invention, a compound having a dehydrating effect which is usually used can be used, but a neutral or alkaline dehydrating agent having a particle size of usually 0.1 to 50 μm is preferable. Examples thereof include hydroxides, oxides or salts of metals belonging to Groups II, III and IV of the Periodic Table of the Elements. Specific examples include barium hydroxide, calcium oxide, calcium sulfate (hemihydrate gypsum), calcium chloride, and zeolite (sodium aluminosilicate). Preferred are calcium sulfate and zeolite.

The amount of the dehydrating agent (C) is usually 1 to 8 parts by weight per 100 parts by weight of the polyol component (A),
It is preferably 2 to 6 parts by weight. If the amount of the dehydrating agent (C) is less than 1 part by weight, the dehydrating effect is insufficient, so that water mixed by moisture absorption reacts with isocyanate to cause a foaming phenomenon, resulting in an uneven density distribution of the obtained polyurethane foam molded product. Prone. Further, even if it exceeds 8 parts by weight, no further dehydration effect is obtained, and the machinability deteriorates.

In the method for producing a foamed polyurethane molded article according to the present invention, a mechanical floss method, that is, a mixer having a high shearing force such as an Oaks mixer is used, and the polyol component (A) and the organic polyisocyanate component (B) are used. It is carried out by mixing an inert gas into the liquid phase composed of the above. The Oaks mixer is a mixer suitable for continuously mixing gas. Other
The inert gas may be mixed in a batch method, for example, a Hobart mixer is used.

The inert gas mixed in by the mechanical froth method of the present invention does not react with the polyol component (A) or the aromatic polyisocyanate component (B) and is at −30 at atmospheric pressure.
Gases that are not liquid at ° C are included. Preferably air,
Nitrogen and carbon dioxide. The volume content of the inert gas in the composition is usually 10 to 80%, preferably 20 to 20%.
70%. Molded product usually has a density of 0.2-0.9g
/ Cm3, preferably 0.3 to 0.8 g / cm3
Is.

In the method for producing a foamed polyurethane molded article of the present invention, by further using the hollow body (D) in combination,
Not only can the weight of the hollow body (D) itself be reduced, but it can also serve as a nucleating agent when an inert gas is mixed, so that the weight reduction effect is further enhanced. Examples of the hollow body (D) of the present invention include closed-cell hollow bodies of inorganic compounds or organic compounds. The size and bulk specific gravity are not particularly limited, but usually the size is 10 to 500 μ, and the bulk specific gravity is 0.01 to 0.5.
0 g / cm3 can be used. Examples of the inorganic hollow body include alumina balloons, glass microballoons, shirasu balloons, carbon balloons, and hollow bodies made of silica and fly ash. Examples of the hollow organic material include phenolic microballoons (phenolic resin hollow body manufactured by Union Carbide), saran microspheres (polyvinylidene chloride hollow body manufactured by Dow Corning), Matsumoto microspheres (polyacrylonitrile resin hollow body manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.). ), Urea resin, polyvinyl acetate, polymethylmethacrylate, polyurethane, and hollow bodies made of synthetic polymers such as epoxy. Preferably, glass mikle balloon, shirasu balloon, phenolic micro balloon,
This is the Matsumoto Microsphere.

The amount of the hollow body (D) is usually 2 to 20 parts by weight, preferably 5 per 100 parts by weight of the polyol.
~ 15 parts by weight. When the amount of the hollow body (D) is less than 2 parts by weight, the cured polyurethane foam molded article is liable to have a density distribution. If it exceeds 20 parts by weight, the viscosity of the composition remarkably increases, and it becomes difficult to mix and stir with an Oaks mixer, and as a result, a homogeneous molded product cannot be obtained.

In the present invention, if necessary, the polyol component (A) may contain another active hydrogen-containing compound, and may be reacted with a part or the whole amount of the aromatic polyisocyanate (B). For example, a small amount of polyamine (tolylenediamine, ethylenediamine, etc.) may be used together in order to increase the reactivity.

In the present invention, a catalyst usually used for polyurethane reaction, for example, an amine catalyst [triethylenediamine, N-ethylmorpholine, diethylethanolamine, 1,8-diazabicyclo (5.4.0) undecene-7, etc.] , Metal catalysts (stannous octylate, dibutyltin dilaurate, lead octylate, etc.) can be used. The amount of catalyst is based on the weight of the reaction mixture.
Usually 0.001 to 5% by weight is used.

If necessary, a colorant (dye, pigment),
Additives such as a plasticizer, a filler, a flame retardant, an antiaging agent, and an antioxidant can also be used.

As a method for producing the molded article of the present invention,
Generally, the following process procedure is typical. (1) A dehydrating agent (C) and, if necessary, a surfactant are uniformly mixed in advance with a polyol component (A) consisting of an aromatic ring-containing polyol (a) and an aliphatic polyol (b). (2) The mixture, the aromatic polyisocyanate (B) and the inert gas are uniformly mixed using an Oaks mixer or Hobart mixer, and then the mixture is poured into a mold. (3) After being cured in the mold, the mold is removed to obtain a polyurethane foam molded product. In addition to this, when the curing reaction is relatively slow, after preliminarily mixing the polyol component (A) containing the dehydrating agent (C) and the aromatic polyisocyanate (B), an inert gas is further uniformly mixed, It can also be injected into the mold.

In the case of stirring with an Oaks mixer,
Mixture of (A) and (C) 5-10 L / min (Temperature 20-4
0 ° C.) and (B) 5-10 L / min (temperature 20-40 ° C.), inert gas 2-10 L / min (pressure 4-10 Kg /
It is desirable to mix cm 2 · G). In the case of stirring with a Hobart mixer, 30-180 rpm
It is generally desirable to stir at a rotation speed of 2 to 15 minutes. According to this method, the density can be reduced and the density distribution can be narrowed. When the stirring time is 1 minute or less, a desired low density cannot be obtained, and the density distribution does not become smaller than that.

The foamed polyurethane molded article of the present invention is suitable as a model material, and is used for a master model, a profile model, a design model, an NC tape confirmation model, a styling model, an inspection jig and the like.

[0032]

The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Parts in the examples are parts by weight, and the molecular weight is the number average molecular weight in terms of hydroxyl number. Example 1 Aromatic ring-containing polyol (I) 30 having a molecular weight of 374 obtained by addition-polymerizing 174 parts of PO to 200 parts of bisphenol F 30
Part, 136 parts of pentaerythritol and 419 parts of PO by addition polymerization, aliphatic polyol (II) 7 having a molecular weight of 555
0 parts, calcium sulfate (hemihydrate gypsum) 6 parts, silicone S
M-ionate MR-200 (Nippon Polyurethane Industry crude MDI, NCO content 31%) 94 in a premix consisting of 4 parts of H-193 (foam stabilizer made by Toray Silicone Co., Ltd.)
After adding parts, with a Hobart mixer, 120 rp
The mixture was stirred for 10 minutes at a speed of m. Next, the foamed polyurethane-forming composition thus obtained was treated with a mold temperature of 35
The mixture was poured into an iron mold (length 20 × width 30 × height 5 cm) adjusted to ˜45 ° C., the lid was closed, and the mixture was cured in the mold. After leaving for 1 hour in a constant temperature bath at 70 ° C., the mold was removed to obtain a foamed polyurethane molded article. The density distribution, heat distortion temperature and dust amount of the obtained molded product were measured. The density distribution is
The polyurethane foam molded product was sliced into a thickness of 5 mm, the density of each section was measured, and the difference was calculated from the difference between the maximum value and the minimum value. The heat distortion temperature was measured according to JIS K6301. The amount of dust is 300mm away from the edge of the flat end mill of the NC milling machine, a small vacuum cleaner (Hand Cleaner HC-V12 made by Matsushita Electric Co .; suction work rate 38W) is installed, and a predetermined cutting length is applied before and after cutting. It was calculated from the change in the weight of the dust bag. The cutting conditions on the NC milling machine at this time are as follows. NC milling machine type: Kikugawa Iron Works CNC router NCE-23-1F Bit type: Flat end mill (Φ
20, HSS) Processing conditions: 3000 rpm (rotation speed): 2000 mm / min (feed rate): 0.2 mm (cut amount): 120 mm x 5 reciprocations (total cutting length 1200 mm)

Example 2 Aromatic ring-containing polyol (III) 20 having a molecular weight of 286 obtained by addition-polymerizing 58 parts of PO to 228 parts of bisphenol A 20
Part, 290 parts of propylene glycol, and 290 parts of PO were added to polymerize aliphatic polyol (IV) 80 having a molecular weight of 366.
Part, 5 parts of calcium chloride, and 4 parts of silicone SH-195 (foam stabilizer made by Torresicone Co., Ltd.), a prepolymer synthesized from TDI-80 (TDI made by Mitsui Nisso Urethane Co., Ltd.) and castor oil (NCO content 31). %,
VII) 81 parts were added and a polyurethane foam molded article was prepared in the same manner as in Example 1.

Example 3 To 228 parts of bisphenol A, 160 parts of a mixture of PO and EO in a weight ratio of 2 to 1 was added and polymerized, 10 parts of an aromatic ring-containing polyol (V) having a molecular weight of 388, and to glycerin of 92 parts, 464 parts of PO was added. 90 parts of polymerized aliphatic polyol (VI) having a molecular weight of 556, 3 parts of hemihydrate gypsum, silicone SZ
To a premix consisting of 2 parts of -1627 (foam stabilizer made by Nippon Unicar), 75 parts of Coronate 1107 (crude MDI made by Nippon Polyurethane Industry Co., Ltd., NCO content 31%) was added, and a foamed polyurethane molded article was prepared in the same manner as in Example 1. It was created.

Example 4 3 parts of an aromatic ring-containing polyol (VII) having a molecular weight of 460 obtained by addition-polymerizing 232 parts of PO to 228 parts of bisphenol A were prepared.
To a premix consisting of 0 part, 70 parts of the aliphatic polyol (II) of Example 1, 3 parts of barium hydroxide, and 4 parts of silicone L-5420 (a silicone foam stabilizer by Nippon Unicar), 89 of Millionate MR-100 was added. Example 1
A foamed polyurethane molded article was prepared by the same method as described above.

Example 5 30 parts of a polyaromatic ring-containing polyol (VIII) having a molecular weight of 346, obtained by addition-polymerizing 146 parts of a mixture of 200 parts of bisphenol F and PO in a weight ratio of 1: 2, and 377 parts of PO to 185 parts of methyl glycoside. Of addition polymerization of 56
70 parts of 2 aliphatic polyol (IX), 4 calcium chloride
Parts, glass micro balloon C-15 (glass hollow body manufactured by Sumitomo 3M), 3 parts of silicone SH-193
143L of Millionate (modified MDI manufactured by Nippon Polyurethane Industry Co., Ltd., NCO content 29%)
A polyurethane foam molded product was prepared in the same manner as in Example 1 except that 101 parts were added.

Example 6 20 parts of an aromatic ring-containing polyol (X) having a molecular weight of 400, wherein 172 parts of PO was added to 228 parts of bisphenol A, and 308 parts of PO was added to 92 parts of glycerin, and a molecular weight of 4 was added.
No. 00 aliphatic polyol (XI) 80 parts, molecular sieve 3A powder 2 parts, phenolic microballoon BJO-0930 (union carbide company hollow body) 1
To a premix consisting of 5 parts and 3 parts of silicone L-5420, 98 parts of Millionate MR-200 was added, and a foamed polyurethane molded article was prepared in the same manner as in Example 1.

Example 7 20 parts of the aromatic ring-containing polyol (I) of Example 1 and 92 parts of glycerin were added and polymerized with 282 parts of EO to give a molecular weight of 37.
80 parts of aliphatic polyol (XII) of 4, 4 parts of hemihydrate gypsum,
Matsumoto Microspheres MFL80ED (Matsumoto Yushi-Seiyaku Co., Ltd. hollow body) 5 parts, to a premix consisting of 3 parts of silicone SZ-1627, 105 parts of Millionate MR-100 was added, and a foamed polyurethane molded article was prepared in the same manner as in Example 1. It was created.

Comparative Examples 1 to 5 Comparative Example 1 was the same as Example 1 except that the polyol component was only the aliphatic polyol (II). Further, the weight ratio of the aromatic ring-containing polyol (I) and the aliphatic polyol (II) is 60
Comparative Example 2 was changed to / 40. Similarly Example 1
Comparative Example 3 was prepared by removing the dehydrating agent (calcium sulfate). Furthermore, the aromatic ring-containing polyol (I) of Example 1 was changed to castor oil as Comparative Example 4, and the 3,3′-dichloro-4,4′-diaminodiphenylmethane was changed to Comparative Example 5, respectively. A foamed polyurethane molded article was prepared in the same manner as in Example 1. The amount of Millionate MR-200 (B) used in this comparative example was 1: 1.04 in terms of the equivalent ratio of the hydroxyl group of the polyol component (A) and the isocyanate group of (B) of each comparative example. Was set. Examples 1-7 and Comparative Examples 1-5
The performance of the molded product is shown in Table 1.

The density distributions of Examples 1 to 7 (difference between maximum and minimum values of density) are all 0.1 g / cm 3 or less, which is smaller than that of Comparative Examples 1 to 3. As in Comparative Example 1, only the aliphatic polyol increases the amount of dust. When the amount of the aromatic ring-containing polyol is large as in Comparative Example 2, the heat distortion temperature is low and the heat resistance is poor. When there is no dehydrating agent as in Comparative Example 3,
Water foams and the density distribution becomes large. In Comparative Examples 4 and 5, the heat distortion temperature is low and the amount of dust is large.

[0041]

[Table 1]

[0042]

Industrial Applicability According to the present invention, since the dust during cutting can be reduced without lowering the heat resistance, the working environment can be improved. Furthermore, since it is possible to obtain a lightweight polyurethane foam product having a uniform density distribution, it is possible to significantly reduce warpage deformation during cutting. Therefore, it is extremely useful in applications such as model materials.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 15, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C08G 101: 00) B29K 75:00 C08L 75:04

Claims (4)

[Claims] 1. An aromatic ring-containing polyol (a) having a hydroxyl value of 200 to 400 represented by the following general formula, and an aliphatic polyol (b) having a hydroxyl value of 250 to 500.
Comprising a polyol component (A), an aromatic polyisocyanate component (B), and the polyol component (A) 10
1 to 8 parts by weight of dehydrating agent (C) per 0 parts by weight,
A method for producing a foamed polyurethane molded article, which comprises foaming by a mechanical froth method containing substantially no foaming agent. [Chemical 1] (In the formula, X is a group selected from H, CH3, Cl, and Br;
Y- is any group of -CH2-, -C (CH3) 2-, -SO2-, -O-, single bond; A is a propylene group or ethylene group; m + n is a number of 0 to 13. ) 2. The weight ratio of (a) and (b) is 10/9.
The method for producing a foamed polyurethane molded article according to claim 1, which is 0 to 40/60. 3. The method for producing a foamed polyurethane molded article according to claim 1 or 2, wherein (b) is an alkylene oxide adduct of a divalent to tetravalent aliphatic or alicyclic alcohol. 4. The method for producing a foamed polyurethane molded article according to claim 1, further comprising 2 to 20 parts by weight of a hollow body (D) with respect to 100 parts by weight of the polyol component (A). .