JPS60206819A - Production of polyurethane molding - Google Patents

Abstract

PURPOSE:To produce a polyurethane molding with good reactivity and self- releasability by a reaction injection molding process, by employing a material containing a specified polyol component. CONSTITUTION:A composition comprising a polymer polyol containing at least 20wt% polyoxyethylene chain-terminated polyol containing internal random polyoxyethylene chains and having a functionality >=5 and an equivalent weight >=1,450, an organic polyisocyanate (e.g., toluene diisocyanate) and, optionally, a blowing agent is poured into a desired mold and reaction injection-molded into a polyurethane molding. By the use of the above material, molding can be repeated about 10-20 times for each application of a releasing agent with good mold releasability.

Description

[Detailed Description of the Invention] The present invention relates to a method for producing polyurethane molded products, specifically a method for producing polyurethane molded products having high reactivity and self-releasing properties, particularly when molded using the RIM method (reaction injection molding method). This invention relates to a method for producing polyurethane molded products that exhibit excellent reactivity and self-releasing properties.

BACKGROUND ART Conventionally, the RIM method has been put to practical use as a means of producing urethane molded products for applications such as automobile exterior and interior materials such as bumpers, instrument panels, and steering wheels. As such, the urethane raw materials for 7cI'RJ M are as follows:
It is required that it has high reactivity and can be cured and demolded in a short time, and it is also required that it has self-releasing properties and can be released from the mold without having to apply a mold release agent each time. .

The present inventors have discovered a raw material polyol and a method for producing polyurethane that satisfy these requirements - As a result of extensive investigation, by using a specific polyoxyalkylene polyol, a polyurethane with high reactivity and self-releasing properties can be produced. It was discovered that a molded article can be obtained, and the present invention was achieved.

That is, the present invention provides a method for producing a polyurethane molded article by reacting an organic polyisocyanate and a polymeric polyol in a mold, if necessary in the presence of a blowing agent. As above), a terminal polyoxyethylene chain-containing polyol (A) having a functional group number of 5 or more and an equivalent weight of 1450 or more is used [However, A) is a polyol (AI) having an internal random polyoxyalkyne chain, or (A1) and 0
~2.0% (consisting of block polyoxyalkylene polyol (A2) of '() based on the weight of the polymeric polyol)], and (2) organic polyisocyanate and polyol without applying mold release agent each time. This is a method for producing self-releasing polyurethane molded products, which is characterized by the introduction of the present invention.

The polyol (A) used as part or all of the polyol (A) in the present invention may be a compound having at least 5 (preferably 6 to 12) active hydrogen atoms (for example, a polyvalent hydrogen atom). alcohol.

Compounds having a structure in which ethylene oxide and other fullylene oxides are added to amines) so as to form the above-mentioned terminal oxyethylene chain and internal random polyoxyalkylene chain, and mixtures thereof can be mentioned.

Examples of the polyhydric alcohol include sugar alcohols such as pentitol such as adonitol, arabitol, and xylitol; hexitol such as sorbitol, mannitol, iditol, talitol, and dulcitol; and sugars such as monosaccharides such as glucose, mannose, fructose, and sorbose.

Oligosaccharides such as sucrose, trehalose, lactose, roughy, and north; gelicosides; e.g. glucosides of polyols (e.g. glycols such as ethylene glycol, propylene glycol; alkane polyols such as glycerin, trimethylolpropane, hexanetriol, pentaerythritol); poly( alkane polyol)
Examples include polyglycerols such as triglycerin and tetraglycerin; polypentaerythritols such as dipentaerythritol and tripentaerythritol; and cycloalkane polyols such as tetrakis(hydroxymethyl)cyclohethinol. Examples of the polyhydric phenol include novolac, such as the polyphenol described in U.S. Pat. No. 8,265,641; and examples of amines include polyalkylene polyamines such as diethylene triamine and triethylene triamine. Two or more compounds may be used in combination.In addition, one or more of these compounds and a compound having 2 to 4 active hydrogen atoms [for example, the combination of 2 listed as a raw material for polyether polyol in (B) below] Mixtures having an average number of functional groups (number of active hydrogen atoms) of 5 or more (preferably 6 to 12) can also be used. Among these, preferred are polyhydric alcohols, especially sorbitol and sucrose.

As another alkylene oxide (hereinafter abbreviated as AO) to be added to the above active hydrogen atom-containing compound together with ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as 1) 0) is usually used, but PO
Add a small amount (for example, 5% or less) of other alkylene oxides (butylene oxide, styrene oxide, etc.) to
They can also be used together.

The polyol (A1) used in the present invention is preferably a compound having at least 5 active hydrogen atoms as described above (base compound) or an alkylene oxide adduct thereof (base polyether), and a combination of ethylene oxide and propylene oxide. A mixture obtained by adding a mixture, then adding alkylene oxide if necessary, and then adding ethylene oxide to the terminal can be used. Such a polyol can be represented by the following general formula.

R((AIO)a'(EO/PO)h(A20)c
(Ei))dH) nIn the formula, R is a residue obtained by removing 11 active hydrogen atoms from a compound having at least 2 active hydrogen atoms; n is an integer of 5 or more i EO/PO is an oxyethylene group and an oxy Random polyoxyalkylene M consisting of a propylene group, EO is an oxyethylene group, A10 and A20 are oxyalkylene groups; a, b, c.

d is 0 or a positive integer, and n a, n su, n
The c's and the n d's may be the same or different. The sum of the n a's and the n c's may be O.

In the present invention, as the polyol (A), a combination of a bipedal polyol (A1) and a block polyoxyalkylene polyol (A2) can also be used. Polyol (A2
) as EO and AO in compounds having at least 5 active hydrogen atoms as described above.

(Added in the order of 1υAO-EO (chipped).

(II) Those added in the order of AO-EO-An-EO (balanced), (song) added in the order of EO-AO-EO, etc. Among these, preferred are (ri) and (11).

The number of functional groups (average) of the polyol (A) ((A4)- or combination of (A1) and (A2)) used in the present invention is 5 or more, preferably 6-12. If the number of functional groups is less than 5, The self-releasing property (the mold can be removed without applying a mold release agent each time), which is the objective of the present invention, cannot be obtained; polyol (A
The equivalent weight (molecular weight per OH) of , ) is 1450 or more, preferably 1500 to 8200, particularly preferably 1600 to
It is 3000. If the equivalent weight is lower than 1450, the physical properties such as temperature characteristics and elongation of the resulting polyurethane will deteriorate. If the equivalent weight exceeds 8,200, the viscosity increases, flowability deteriorates, and reactivity decreases, which is not preferable.

(A) terminal polyoxyethylene chain content (hereinafter referred to as terminal E
The amount of O (abbreviated as O amount) is usually 10% (weight%, the same applies hereinafter) or more, preferably 12 to 80%, more preferably 15 to 2
It is 8%. If the amount of terminal EO is less than 10%, the reactivity is low, the curing property is low, the initial physical properties are low, and it is impossible to mold a polyurethane that has self-releasing properties, especially RI M.
In the case of molding by the method, a satisfactory effect cannot be obtained. In addition, if the amount of terminal EO exceeds 80%, the curing properties will improve, but the viscosity will increase and it will become cloudy at a temperature slightly lower than room temperature, resulting in poor workability, and physical properties such as temperature characteristics and water absorption will deteriorate. Undesirable.

In addition, even if the amount of terminal EO is less than 10%, the amount of terminal EO is 1.
In combination with 0% or more, or in combination with 30% or less of terminal EO in excess of 80%, it is blended so that the overall ('average) terminal EO content falls within the above range. Use C! : Can be done. The same applies to C in terms of equivalent weight and number of functional groups4.Also, the total polyoxyethylene chain content of (A) (abbreviated as the amount of μ undercoat EO) is usually 10% or more, preferably 12-40%, and more preferably 15-40%. 30
1, which is %.

In addition, in the polyol (A,), a random polyoxyalkylene chain in the polyether polyol chain -
(EO, /PO) The ratio (weight ratio) of oxyethylene group to oxypropylene group in b- is usually 90:10
~30:70, preferably 80:20 to 40:60, more preferably 75:25 to 45:55. When the proportion of oxyethylene groups exceeds 90, crystallinity improves, so that the obtained polyether polyol becomes cloudy when cold (at a temperature slightly lower than room temperature). Also, because the reactivity becomes too high, defects are likely to occur on the surface of the molded product. On the other hand, if the proportion of oxyethylene groups is 80% terminal, the internal activation force will be weakened, the curing property will be reduced, and the initial physical properties of the molded product will be poor. The content of said random polyoxyalkylene chains in the polyether polyol is usually at least 5%, preferably from 5 to 25% of the total molecule.

The proportion of random polyoxyalkylene chains is 5% of the total molecular weight.
If it is less than %, the internal activation force is small and the curing property is low, so that only a molded product with low initial strength can be obtained. If it exceeds 25%, the water absorption of the molded product is high and the reactivity is too high, which tends to cause defects in the surface condition of the molded product. The proportion of oxyethylene groups present in the polyoxyalkylene resin described in
% is preferably 2.0 to 20%. Polyol (A1
) The position of the random polyoxyalkylene chain (the addition position of the ethylene oxide-propylene oxylide mixture) is preferably placed at the end of 60% of the total molecular weight.
Yes.

That is, the base polyether (R(-(A, 0
), H, :l, , ) is preferably set such that the molecular weight ratio is 60%. 1-Alkylene oxide (A1) used for forming the base polyether
Propylene oxide is usually used as the 0), but a small amount (for example, 5% or less) of other alkylene oxides (ethylene oxide, bunalene oxide, styrene oxide, etc.) can also be used in combination with it. The OH number of the base polyether is 28 to 83 (especially 2
5 to 67) are preferred.

Even if the random polyoxyalkylene chain and the terminal polyoxyethylene chain are directly bonded, it is still a polyoxyalkylene chain (A20). - may be bonded via. In the latter case, propylene oxide is usually used as the alkylene oxide (A2'O) used to form the intervening polyoxyalkylene group, but other alkylene oxides (having 4 or more carbon atoms such as butylene oxide and styrene oxide) are also used. A small amount (for example, 5% or less) of alkylene oxide) can also be used in combination.

In the present invention, polyol (A) ((A+) and (
A2)] may be a so-called polymer polyol modified with an ethylenically unsaturated monomer.

Monomers used in the production of polymer polyols include:
The following may be mentioned: (1) Acrylic acid, methacrylic acid and derivatives thereof: acrylonitrile, methacrylonitrile.

Acrylic acid, methacrylic acid and their salts.

Methyl acrylate, methyl methacrylate, dimethylaminoethyl methacrylate, acrylamide, methacrylic acid amide, etc.

(It) Aromatic vinyl monomer: styrene 8-dermethylstyrene, etc.

(Song) Olefinic hydrocarbon monomers: ethylene, propylene, butadiene, isobutylene, isoprene, 1.4
-Pentagene etc.

(1v) Vinyl ester monomer: vinyl acetate, etc.

(V) Vinyl halide monomer: vinyl chloride, vinylitine chloride, etc.

(vl) Vinyl ether monomer: vinyl methyl ether, etc.

Among these, preferred is acrylonitrile.

These are methyl methacrylate, styrene, and butadiene. Particularly preferred is acrylonitrile, or a combination of acrylonitrile and styrene (weight ratio In of styrene:acrylonitrile: 90 to 60:40).

The polyol (A) is partially modified with an intermediate (for example, modified (A1) and unmodified (A1)).
A4) e-modified (A1) and unmodified (A,2:l-
Alternatively, a combination of unmodified (A1) and modified (A2)] or a combination of both unmodified (A1) and modified (A2) may be used.

In addition, the polyol (A) may be used with other polyols [
For example, it may be modified with a monomer by mixing it with a polymeric 7JP reol and/or a low-molecular polyol listed as examples of (B) and (C) below.

In this case, 1J of unmodified (A) in the polyol self-measurement
is usually 20% or more, preferably 50% or more, and the star of low molecular weight polyol is usually 20% or less.

The ratio of the monomers used for modification can be varied over a wide range, but usually the proportion of ethylenically unsaturated monomer ( or in serious condition) 2-7
0 parts by weight, preferably 5 to 40 parts by weight.

Modification of a polyol with an ethylenically unsaturated monomer (manufacturing a polymer polyol) can be carried out by a conventional method. For example, a method of polymerizing an ethylenically unsaturated monomer in a polyol in the presence of a polymerization catalyst (such as a radical generator) (US Pat. No. 8,888,851, Japanese Patent Publication No. 89-2478)
No. 7, Special Publication No. 47-47999, Japanese Patent Publication No. 158-1973
No. 94) and a method in which a polymer obtained by pre-polymerizing the above monomers and a polyol are graft-polymerized in the presence of a radical generator (Japanese Patent Publication No. 47-47597 (j). The former method is preferred. Azo compounds are used as polymerization catalysts (radical generators) for polymerization reactions.

Peroxides, persulfates, perborates, etc. can be used, but azo compounds are practically preferred. The amount used is not particularly limited, for example, ethylenically unsaturated monomer (or (
The amount is 0.1 to 2 Oi parts, preferably 0.1 to 15 parts by weight, per 100 parts by weight of the polymer. The polymerization described in -J- can also be carried out in the presence of a solvent such as toluene, xylene, etc. The reaction temperature is usually 50-170°C, preferably 90-150°C.

To implement the polyurethane manufacturing method of the present invention! -14, the polyol (A) is used alone or in combination with other polymer polyols (B) or/and low molecular active hydrogen-containing compounds (
This can be carried out by reacting with organic polyisocyanate-1 in combination with C). As other polymeric polyols (B) that may be used in combination, polyether polyols, polyester polyols, and polymer polyols other than (A) can be used. Examples of polyethylpolyols other than (1) include compounds having 2 to 4 active hydrogen atoms (low-functionality polyhydric alcohols include ethylene glycol, diethylene glycol, propylene diglycol, 1, Dihydric alcohols such as 4-butanediol, opentyl glycol Hj-71, ■, 6-hexanediol, trihydric alcohols such as glycerin, trimethylolpropane, hexanetriol, triethanolamine, and pentaerythritol.

Tetrahydric alcohols such as Mediculg IQ coside; alkylene oxide (Ao such as E O and/or PO) adducts of polyhydric phenols such as hydroquinone, bisphenol A, amines such as ethylenediamine, aminoethylpiperazine, etc., polytetramethylene Low-functionality polyether polyols such as ether glycols; polyether polyols with a functional group number of 5 or more that do not have terminal polyoxyethylene chains ((less than 0%) (P
O adducts, P O,/E O random adducts, PO/EO block adducts having a polyoxyethylene chain only inside, etc.), or those having an equivalent weight of less than 1450. As the polyester polyol, the above-mentioned low-functional polyalmol (ethylene glycol) is used.

Dihydric alcohols such as glycol and alcohol are combined with glycerin, trimethylolpropane, etc.
polycarboxylic acids (e.g., adipic acid, maleic acid, phthalic acid, etc.) or their anhydrides and alkylene oxides (e.g., EO, PO, etc.).
(ζ') obtained by reacting (condensing) or ring-opening polymerization of lactone (such as ε-caprolactone). As the polymer polyol, these polyols (polyethyl) 9-liol and
polyol obtained by polymerizing an ethylenically unsaturated monomer (acrylonitrile, ethylene, etc.)
No. 899, and those described in Japanese Patent Application Laid-open No. 54-J22896). Among (B), preferred are polyethyl polyols 1''. In particular, low-functionality polyether polyols having terminal polyoxyethylene chains (diols and/or triols,
Terminal EOffi 10-30%):] and its] polymer polyol.

High molecular polyol [The amount of (A) in the total amount of (A) and (B) J if necessary is usually 20% or more, hf
Preferably it is 80% or more, more preferably 40% or more. If (A) is less than 20%, a polyurethane with good curing properties, initial physical properties and self-releasing properties cannot be obtained. In addition, polymer polyol [(A) and if necessary (B>il
When (1) (polymer polyol) modified with a monomer is used as at least a part of the unmodified (A) portion of the unmodified polymer polyol portion (excluding the polymer portion) The ratio is usually 20% or more, preferably 3
It is 0% or more, more preferably 40% or more.

Note that the amount of (A2) in the polymer polyol is less than 20% by weight.

The terminal Eo content of the entire polymer polyol is usually 10% or more -1
- Preferably 12-30%, more preferably 15-30%
It is Z%. Equivalent weight of entire high molecular weight polyol (average)
is usually J450~aoooo preferably 1600~280
0 - optionally used low-molecular active hydrogen-containing compound (C'
) As C, a chain extender such as a low-molecular diol, diamine, amino alcohol, etc. can be used.

Examples of low-molecular diols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, neopentyl glycol, hexanediol, polyethylene glycol and polypropylene glycol with a molecular weight of 200 to 400, and low-molecular diols having a cyclic group ( For example, special public relations
1474; bisphenol A propylene 1/1' toy-sized additives, etc.), 8th or quaternary nitrogen atom-containing low molecular weight di-ols (for example, JP-A-54-1
．． Those described in No. 80699: Alkyl diano 1. Examples include carbonylamine, etc. and quaternized products thereof), thiodilene glycol, and the like. Examples of diamines include toluenediamine, xylylenecyamine, diethyldiaminotolamine, diaminodiphenylmethane, methylenebis-〇-chloroaniline, diaminophenylsulfone, dichlorobenzidine, and dianisidine.

Aromatic diamines such as 0-nitro-D-phenylene diamine; cycloaliphatic diamines such as isophorone diamine, dicyclohexylmethane diamine, cyclohexylene diamine; ethylene diamine, propylene diamine, hexane diamine, 2,2,4-trimethylhexane diamine, etc. Examples include aliphatic diamines and heterocyclic diamines such as piperazine. Examples of amines and alcohols include ethanolamine, propatoolamine, ethylethanolamine, phenylethanolamine, 8-aminol 2-
Methyl-1-bropatur etc. cause vignetting. Among these, preferred are low molecular diols (especially ethylene glycol, 1,4-butanediamine, neopentyl glycol) and diamines (especially toluenediamine,
diethyldiaminotoluene). By using a chain extender in combination, the amount of heat generated during the reaction with the isocyanate becomes larger, thereby improving the curing property. In addition to the flexibility possessed by polymeric polyols, the hardness increases due to the increased concentration of urethane bonds (or urea bonds) in the molded product, resulting in a molded product with high physical properties that has a good balance of rigidity and flexibility. can get.

The amount of (C) used (if a low molecular weight polyol is contained in the polymer polyol, this amount is also included).

The same applies hereinafter) can be varied depending on the required performance (rigidity, etc.). In the case of low-molecular-weight diols, the amount used is usually 80% or less, preferably 4 to 25% of the total polyol. When a diamine is used, it is used in a smaller amount than the above, for example, 10% or less, preferably 1 to 8%, based on the total amount of polyol and amine.

If the amount of chain extender is greater than the above, the urethane becomes too rigid, resulting in a decrease in initial strength, elongation, and impact properties. The molar ratio of polymer polyol and chain extender is usually 1:2
The ratio is 0 to 160, preferably 1:25 to 140.

As (C), a chain extender is preferable, but in place of or in addition thereto, a crosslinking agent such as trivalent or higher valent agent such as glycerin, trimethylolpropane, 1-liethanolamine, tris or tetrakis(bido-b-xypropyl)ethylenediaminediethyldiaminotoluene, etc. It is also possible to use low molecular weight polyols. The use of a crosslinking agent lowers the viscosity of the reaction system, lowering the flowability during mold injection and elongation of the physical properties of the molded product, and increasing the hardness, so it is preferable not to use it, and if used, use a small amount to prevent chain elongation. dosage of 20
% amount or less.

The average equivalent weight of all active hydrogen components [(A) and optionally (B) and/or (C)] is usually 120 to 1000.
Preferably it is 140-900.

As the organic polyisocyanate used in the present invention, those conventionally used in the production of polyurethane can be used. For example, aliphatic polyisocyanates (hexamethylene diisocyanate).

lysine diisocyanate, etc.), alicyclic polyisocyanates (hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, etc.), aromatic polyisocyanates [toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthi diisocyanate, xylylene diisocyanate, etc.] and mixtures thereof.

Among these, aromatic diisocyanates are preferred, and TDI and MDI are particularly preferred.

These polyisocyanates are crude polyisocyanates, e.g. crude TI') I, crude MDI (crude 11 diaminophenylmethane 1 condensation product of formaldehyde and aromatic amines or mixtures thereof; diaminodiphenylmethane and small amounts (e.g. 5 to 20 wt. %) of trifunctional or higher functional polyamines (polyallylpolyisocyanate) CPAPI)), or modified polyisocyanates such as liquid MDI (carposiimide modified).

It can also be used as a prepolymer containing free isocyanate obtained by reacting excess polyisocyanate (TDI, MDI, etc.) with a polyol (trihydrocarbyl phosphate modified, etc.), or in combination (
For example, a modified polyisocyanate and a prepolymer may be used in combination.

Polyols used in the production of the prepolymer include polyols having an equivalent weight of 30 to 200, such as ethylene glycol, propylene glycol, diethylene glycol,
Glycols such as dipropylene glycol; triols such as trimethylolpropane and glycerin; high-functional polyols such as pentaerythritol and sorbitol;
and alkylene oxide (ethylene oxide and/or propylene oxide) adducts thereof. Among these, preferred ones have a functional group number of 2 to 3.
belongs to. The free isocyanate group content of the above-mentioned modified polyisocyanate and prepolymer is usually 10 to 33
% preferably 15-80% particularly preferably 20-29
%belongs to.

For each ζ of producing polyurethane using polyol (A) according to the present invention, polyurethane foam may be produced by foaming, or polyurethane resin (
elastomers, sheets) may also be manufactured. In the former case, the total density of the polyurethane (foam) produced is usually o,
a g/at 1 or more, preferably 0.5 g/ad
As mentioned above, it is particularly preferable to carry out foaming so that the ratio is 0, gg/crd or more. Total density is 08g/cr
If the temperature is lower than d, a polyurethane resin with excellent self-releasing properties cannot be produced.

Foaming is usually carried out using a foaming agent, but foaming can also be carried out by introducing a gas such as air during molding (air loading).

As the blowing agent, water and/or a halogen-substituted aliphatic hydrocarbon blowing agent (fluorocarbons such as trichloromonofluoromethane) can be used. The amount of water used is usually 0.4% or less, preferably 0.2% or less, based on the polymer polyol (polyether polyol). If the amount of water used exceeds 0.4%, carbon dioxide gas generated through the reaction will be exposed to the surface as bubbles, impairing the appearance of the molded product. In addition, in terms of physical properties, the increased strength of the urea bond increases the hardness and increases the brittleness, especially at low temperatures, which is undesirable. The amount of halogen-substituted hydrocarbon foaming agent to be used without water is resin raw materials (organic polyisocyanate, polymer polyol, chain extender).

It is usually 30% or less (preferably 2 to 20%) based on the weight (total of crosslinking agents), and 0.4% or less (preferably 2 to 20%) based on the weight of the polymeric polyol.
% of water is preferably used in combination, it is usually 20% or less (particularly 0 to 15%) based on the weight of the resin raw material.

The ratio of polyisocyanate and active hydrogen atom-containing compound (polymer polyol, complex extender, crosslinking agent, water) may be the same as that of ordinary polyurethane (resin, foam) (NG
For example, the O index is 95 to 120, especially 100 to 11.
0). It is also possible to form a polyisocyanurate (resin, foam) by using an excess of isocyanate (for example, an index of 120 to 1000, especially 150 to 500).

Further, if necessary, the reaction can be carried out in the presence of a catalyst (eighth amines, organic tin compound, organic lead compound, etc.), surfactant (silicone surfactant, etc.), and other auxiliary agents. If necessary, pigments, fillers, flame retardants, solvents, internal mold release agents, thixotropic agents, etc. may be added.

In the method of the present invention, when reacting the organic polyisocyanate with the polyol (A) and optionally (B) and/or (C) in the mold, without applying a mold release agent to the mold each time, Introduce these. That is,
After a mold release agent is once applied to the mold, raw materials are introduced, and the molded product is demolded, the raw materials are introduced and the mold is demolded continuously without applying a new mold release agent. Once the mold release agent is applied, it is possible to perform continuous mold release multiple times, for example, 5 times or more, particularly 10 to 20 times.

The polyurethane production method may be the same as conventional methods, except that it is not necessary to apply a mold release agent each time, and either the one-shot prepolymer method (quasi-prepolymer method) can be applied.

The polyurethane manufacturing method of the present invention is particularly useful for molding by the RIM method, but can also be applied to other methods such as injection molding using a low-pressure foaming machine.

A polyurethane molded article can be produced by a conventional method. For example, a polyol, a chain extender, a crosslinking agent, a catalyst, and if necessary a blowing agent (water and/or fluorocarbons), a pigment, and a foam stabilizer are added and mixed uniformly to form part A, and part B is an organic isocyanate prepared in advance. Prepare and fill tanks A and B of the high-pressure foaming machine. Connect the injection nozzle of the high-pressure foaming machine to the injection port of the mold in advance and add liquid A using the mixing head.

Mix B liquid, inject into a sealed mold, and mold after hardening.

According to the present invention, at least a part of the polyol has a terminal polyoxyethylene chain-containing polyol (A) having a functional group number of 5 or more and an equivalent weight of 1450 or more [internal random polyoxyalkylene chain-containing polyol (AI), or (A1)]
and block polyoxyalkylene polyol (A2
)] to react with an organic polyisocyanate, the strength of the resin is greatly improved, with quick curing, excellent self-releasing properties, and a polyurethane with excellent initial strength. In addition, the polyol (A) has excellent curing properties and requires only a small amount of catalyst, thereby avoiding deterioration in the physical properties and heat resistance of polyurethane due to the use of a large amount of catalyst.

Furthermore, when using a monomer-modified (polymer polyol) as at least a part of (A), the stiffness tends to increase, so compared to the case where an unmodified one is used, the chain extender Since the amount used is small, it is possible to avoid a decrease in the elongation of the molded product, and the amount of expensive isocyanate used can be reduced; it is also possible to reduce the amount of chain extender, which reduces the concentration of urethane groups that have adhesive strength with metals etc. It has advantages such as a relative decrease in the amount of molding and further enhancing the self-releasing effect. Furthermore, in the case of painting polyurethane molded products, molded products that use a large amount of catalyst to speed up curing have the disadvantage that the paint color changes over time. Such problems do not occur. In addition, in the present invention, when the polyol (A) is used in combination with a chain extender, the concentration of verarethane bonds increases compared to when it is not used in combination, so the calorific value further increases, the initial strength increases, and the curing property is further improved. It also has excellent effects in that it improves curing properties while maintaining the viscosity of the urethane reactant low and has a good balance between elongation and hardness in the physical properties of molded products.

The present invention, in which the above-mentioned Reisanrin polyol (A) and organic polyisocyanate are reacted and molded by the RIM method, is superior to conventional methods in the following points: 1) Excellent curing properties Therefore, it is highly effective in shortening the cycle time from injection to demolding, which is the original purpose of the RIM method.

II) Even with a small amount of catalyst, the curing property is excellent, so the increase in viscosity when reacted with polyisocyanate is moderate, and it is possible to avoid insufficient filling and the formation of voids caused by poor flowability in the molded product.

1iii) Conventional methods for increasing curing properties require a large amount of catalyst, resulting in a significant drop in the physical properties of molded products, whereas the RIM method of the present invention requires only a small amount of catalyst, so molded products using catalysts Problems such as deterioration of physical properties and discoloration of painted molded products do not occur.

iv) Excellent curing properties even with a small amount of catalyst, so the viscosity increase is modest when reacting with polyisocyanate, but the mold quickly reaches the cream state, which is the state before reaction curing. When the urethane flows inside the mold, it flows and hardens without penetrating the uneven surfaces on the mold surface, so the adhesion between the mold surface and the urethane is weak, and the resistance during demolding is extremely small, making it difficult to release the urethane from the outside. Once sprayed with a molding agent, it has a self-releasing property that allows it to be released continuously 5 times or more, especially 10 to 20 times.

Furthermore, the method of the present invention exhibits excellent self-releasing properties in various polyurethane molded product manufacturing methods (foam, elastomer, sheet, etc.) in addition to the RIM method. It exhibits excellent effects in polyurethane manufacturing methods that use chain extenders.

The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. (The parts shown in the examples are parts by weight.) The components used in the following examples and comparative examples are as follows.

Polyol 1: Added 9738 parts of propylene oxide to 182 parts of sorbitol, then 3200 parts of a mixture of ethylene oxide and propylene oxide in a weight ratio of 5:5, and then 480 parts of propylene oxide, and then ethylene oxide) 2400 parts A polyether preol with an equivalent weight of 2670 obtained by adding 100% of the polyether preol.

Polyol ■: 92 parts of glycerin and 228 parts of sucrose were mixed to give an average functional group number of 5, followed by 5455 parts of propylene oxide, then 1200 parts of a mixture of ethylene oxide and propylene oxide in a weight ratio of 6:4, followed by A polyether polyol having an equivalent weight of 1650 was obtained by adding 1275 parts of ethylene oxide.

Polyol ■: A polyol with an equivalent weight of 2004 obtained by adding 10058 parts of propylene oxide to 842 parts of sucrose, then 2400 parts of a mixture of ethylene oxide and propylene oxide in a weight ratio of 5:5, and then 8200 parts of ethylene oxide. ether polyol.

Polyol (2): Bool having an equivalent weight of 2,500 obtained by reacting 1,100 parts of a polyol with 1 part of acrylonitrile as an ethylenically unsaturated monomer at a temperature of 180°C and using 1.0 part of azobispributynitrile as an initiator.

Polyol V: A polyether polyol with an equivalent weight of 2000 obtained by adding 9418 parts of propylene oxide and then 2400 parts of ethylene oxide to 182 parts of sorbitol.

Polyol A: polyether polyol of fi 2380 obtained by adding 4908 parts of propylene oxide and then 2000 parts of ethylene oxide to 92 parts of glycerin.

Polyol B: Add 4,660 parts of propylene oxide to 136 parts of erythritol, then add 1,200 parts of a mixture of ethylene oxide and propylene oxide in a weight ratio of 5:5, and then add 1,500 parts of ethylene oxide. A polyether polyol with an equivalent weight of 1870 was obtained.

Polyol C: polyol with an equivalent weight of 2000 obtained by adding 2824 parts of propylene oxide to 76 parts of propylene glycol, then 1000 parts of a mixture of ethylene oxide and propylene oxide in a weight ratio of 5:5, and then 600 parts of ethylene oxide. ether polyol.

A polyol having an equivalent weight of 8,500 obtained by reacting 100 parts of polyether polyol A with 25 parts of acrylonitolyl as an ethylenically unsaturated monomer at a temperature of 18,000 ℃ using 1.0 part of azobisisobutyronitrile as an initiator.

Daiflon llu; Daikin Industries, Ltd. Freon-11 black toner; carbon black, anti-aging agent, (mixture of ultraviolet absorber, antioxidant, heat resistance improver, etc.) dispersed in polyether polyol.

DABCO88LV: Amine catalyst manufactured by Sankyo Air Products.

DABCODC-2: Catalyst manufactured by Sankyo Air Products.

DBTDL: Dibutyltin dilaurate omelette UL-28: Chemical upgrade ■ Handling tin catalyst.

Sumidur PC: Modified Mr manufactured by Sumitomo Bayer Urethane Co., Ltd.
)1 Million MTL: ,. circle,. E-14゜2) Japan'") ') kl>
Modified MD "Resilient B-511" manufactured by Chukyo Yushi Co., Ltd.: External mold release agent manufactured by Chukyo Yushi Co., Ltd. (used for molding of Table 2-4 and 6) The appearance and analytical values of the above polyol are shown in Table 1.

Table 1 Analytical Values of Each Polyol Example and Comparative Example Using polyols 1 to V and polyols A to D, high density polyurethane was formed under the following conditions.

That is, the main components are polyol, a chain extender, and a catalyst.

The polyol component (A liquid) and the isocyanate component (3 liquids) were charged into the raw material tank of a high-pressure foaming machine, and after mixing liquids A and B in the high-pressure foaming machine, the molded products in Tables 2 to 5 had a thickness of 2. 5 mm Width 400111116 Length 1000 cm A multi-plate closed mold (hereinafter abbreviated as flat plate mold) that can control the temperature, and Tables 6 to 7 are injected into a flat plate mold with the thickness of the molded product changed to 5 mm. High-density and medium-density polyurethane molded products were created using this method.

〔Molding condition〕

Discharge amount: Approx. 20-40kg15J Discharge pressure (A liquid/B liquid) (kg/cdIG): 1
60/150 injection time: Approximately 1.5 to 2.2 seconds Raw material temperature (both A and B liquids): Approximately 40°C Mold temperature
: Approximately 70°C Incyanate Index: 105 The molding recipe and the physical property values of the obtained high density polyurethane are as shown in Tables 2 to 7.

The diameter of the molded polyurethane was measured under the following conditions. The molded products in Tables 3 and 5 were annealed at 120°C for 30 minutes after being released from the mold, and then left at 25°C x 60% RH for 3 days before measurement. The molded products in Table 7 are 25°C x 60% R after being released from the mold.
Measurements were taken after leaving the sample at H for one week or more.

Note) The mold release time and physical properties are as follows.

Mold release time: Time from the start of pouring the reaction solution into the mold until it is taken out Initial strength -1; Immediately after taking the molded product out of the mold, the time from the start of injection until the end of the molded product is bent 180 degrees and no cracks appear ( seconds).

Initial strength - Il: Immediately after taking out the molded product from the mold, punch it out with a No. 1 dumbbell to create a sample for tensile strength measurement.

Then, this sample was released from the mold for 60 seconds. Measure the tensile strength at the point of initial strength. It was a degree.

Number of times of self-release: After applying an external mold release agent to a mold once, the number of times continuous molding is performed to obtain mold release properties similar to those obtained during application. As the molds, flat plate molds and actual molds (Table 29, Table 4, a mold for producing passenger car bumpers; Table 6, a mold for producing passenger car handles) were used.

Tear strength: Dumbbell type B, crosshead speed 50m
m/min bending modulus: sample 25 x 125 x 2.
! i mm span 40mm Loading nose 5R Cross head speed tomm/min Chart speed 100mm Z minute heat sag: Sample 25 x 125 x 2.5
mm The sample above was left for 120"CX1hr with a 100mm overhang. After that, the sample was cooled at room temperature for 30 minutes and the distance it sagged was measured.

Brittleness temperature: Based on JTS K-6801.

Table-2 Molding recipe, mold release time, and initial bow density ≦ Table-3 Physical properties of molded product Table-6 Molding recipe, mold release time, and self-release property Table-7 Initial strength-■ and molded product physical properties

Claims (1)

[Scope of Claims] 1. A method for producing a polyurethane molded article by reacting an organic polyisocyanate and a polymeric polyol in a mold in the presence of a blowing agent if necessary, comprising: (1) at least a portion of the polymeric polyol ( (20% by weight or more), a terminal polyoxyethylene chain-containing polyol (A) having a functional group number of 5 or more and an equivalent weight of 1450 or more [However, A) is a polyol (A1) having an internal random polyoxyatkylene chain, or (A,) and 0 to 20% (based on the weight of the polymeric polyol) of a block polyoxyalkylene polyol (A2)], and (2)
A method for producing a self-releasing polyurethane molded article, characterized in that an organic polyisocyanate and a polyol are introduced without applying a mold release agent to the mold each time. 2. The manufacturing method according to claim 1, wherein the terminal polyoxyethylene chain content of (A) is 10% by weight or more. 8. The manufacturing method according to claim 1 or 2, wherein the polyoxyethylene chain content of (A) is 10 to 80% by weight. 4. (A) and other polymer polyols CB) or ・'
and a low-molecular active hydrogen-containing compound (C). 5. The production method according to claim 4, wherein CB) is a terminal polyoxyethylene chain-containing diol and/or triol. Claim 4, wherein 6(C) is a low molecular diol
Or the manufacturing method described in Section 5. ? , 4 to 4 based on the total weight of (A), (B), and (C)
A method according to any of claims 4 to 6, using 25% of (C). 8. The manufacturing method according to any one of claims 1 to 7, wherein at least a portion of A3 is a polymer polyol modified with an ethylenically unsaturated monomer. 9. Total density is 0.5 g/a
The manufacturing method according to any one of claims 1 to 8, wherein an amount of +f or more is used. 10. Claims 1 to 1, which are molded by the RIM method.
The manufacturing method according to any of Item 9.