JPS6051707A - Production of polyurethane elastomer - Google Patents

Abstract

PURPOSE:To obtain a freely releasable polyurethane elastomer, by mixing a high-MW, active hydrogen-containing compound with a chain extender, a polyisocyanate, and a specified nonionic surfactant and curing the mixture in a mold. CONSTITUTION:A reaction mixture of an active hydrogen-containing compound essentially consisting of a high-MW, active hydrogen-containing compound and a chain extender with a polyisocyanate compound and a nonionic surfactant of HLB <= about 18, comprising an adduct between an ethylene oxide-based monoepoxide and an amine or alkanolamine having a long-chain aliphatic hydrocarbon group, is cured in a mold. This surfactant is reactive with an isocyanato group, so that it is preferably premixed with the active hydrogen-containing compound.

Description

[Detailed Description of the Invention] Kinoe IJIJ relates to a method for producing self-releasing polyurethane elastomers by reaction injection molding, etc., and in particular uses a specific nonionic surfactant as an internal mold release agent. The present invention relates to a method for producing a polyurethane elastomer characterized by the following.

At least an active hydrogen-containing compound component such as a relatively high-molecular-weight polyol, which essentially includes a high-molecular-weight active hydrogen-containing compound and a chain extender, and optionally contains a catalyst and a blowing agent, and an incyanate component, which essentially includes a polyisocyanate compound. A method for producing polyurethane elastomers such as polyurethane elastomers and polyurethane urea elastomers by reaction injection molding using two components is known. A typical example of a high molecular weight active hydrogen-containing compound is the above-mentioned relatively high molecular weight polyol, which will be described below as a high molecular weight polyol unless otherwise specified. The chain extender is a relatively low molecular weight polyhydric alcohol or polyamine, which is also a type of active hydrogen-containing compound. The use of a catalyst is usually essential, but it can also be added to the incyanate component. Using a small amount of a blowing agent such as a halogenated hydrocarbon blowing agent to produce a microcellular polyurethane elastomer is a commonly used means for improving moldability. Furthermore, it is also known to divide the active hydrogen-containing compound component into two or more components and perform reaction injection molding using three or more components in total, including the isocyanate component.

In the method for producing a boron 1/tan elastomer by reaction injection molding, it is essential to apply a mold release agent to the inner surface of the mold. The reactive mixture, which is a mixture of a polyol component and an incyanate component, is reacted and cured in a mold, cured to an extent suitable for demolding, and then demolded.

The polyurethane elastomer obtained at this time easily adheres firmly to the surface of the mold and is extremely difficult to release from the mold without a mold release agent. However, the use of a mold release agent that is applied to the inner surface of the mold (hereinafter referred to as an external mold release agent) is a major obstacle to shortening molding time. In injection molding, the use of an external mold release agent is not necessary, or even if it is necessary, its life is sufficiently long, i.e. #! of one external mold release agent. A large number of moldings can be formed from cloth. However, in reaction injection molding of polyurethane elastomers, the life of the external mold release agent is extremely short, and it is necessary to repeat the application of the external mold release agent frequently. Moreover, the application process of the external mold release agent is usually complicated and takes a long time. It takes. Therefore, the time required for applying the external mold release agent to the average molding time per molded product is extremely large, and unless the time required for applying the external mold release agent is shortened, the molding time cannot be shortened. We are in an extremely difficult situation.

In order to extend the life of the external mold release agent, attempts are known to improve the mold release properties of the polyurethane elastomer itself. A typical method is the use of internal mold release agents. That is, an internal mold release agent is blended into the reactive mixture to reduce the adhesion of the resulting polyurethane elastomer, and even if this eliminates the need to use an external mold release agent, it may shorten its lifespan. It is possible to extend it significantly. For example, Japanese Patent Publication No. 5FL-11974 describes an example in which a specific organosilicon compound is used both as an external mold release agent and as an internal mold release agent, and Japanese Patent Publication No. 5C-117 [1974] and A specific internal #type agent is described in Publication No. 198 of 1983. but,
The effects of these internal mold release agents are still not sufficient, and they are also inconvenient to handle. For example, the carboxylic acid group-containing organosilicon compounds described in the first two of the three publications mentioned above tend to deactivate the catalyst necessary for the production of polyurethane elastomers, so they cannot be used at a stage before they are made into a reactive mixture. The two cannot coexist. Therefore, a component containing a catalyst and a component containing the internal mold release agent are required, and since neither can be added to the incyanate component, it is necessary to perform reaction injection molding using at least three components. This is difficult to apply to reaction injection molding equipment that uses two-component raw materials, which are currently widely used.

The present inventors have studied internal mold release agents that can be applied to the production of polyurethane elastomers by reaction injection molding.

The internal mold release agent does not simply have to be non-stick itself.

For example, the internal mold release agent needs to have a high affinity with the components containing it, otherwise it will be easily separated from other components and it will be difficult to obtain a polyurethane elastomer with a uniform composition. In addition, compatibility with the polyurethane elastomer is also necessary; for example, low molecular weight compounds that are not chemically bonded to the polyurethane elastomer may leach onto the surface of the polyurethane elastomer and reduce its paintability. be. That is, if a large amount of the non-adhesive internal mold release agent leaches onto the surface of the polyurethane elastomer, the paint will easily peel off in the case of #i-coated polyurethane elastomer.

The present inventor conducted various studies on internal mold release agents that are effective in the production of polyurethane elastomers by reaction injection molding, etc., and as a result, discovered that certain nonionic surfactants are particularly effective. This non-f-one surfactant is a monoepoxide adduct of amines having a long-chain aliphatic hydrocarbon group, mainly containing ethylene oxide, and has an HLB value of about 18 or less. The present invention relates to a method for producing a polyurethane elastomer whose #I characteristic is to use this specific nonionic surfactant as an internal mold release agent.

A method for producing a non-foamed or mylocellular polyurethane elastomer by curing a reactive mixture of a polyisocyanate compound and a high molecular weight active hydrogen-containing compound and a chain extender-containing active hydrogen-containing compound in a mold. is a monoepoxadide mainly containing ethylene oxide of amines or alkanolamines having long-chain aliphatic hydrocarbon groups in the reactive mixture;
A method for producing a polyurethane elastomer with excellent internal II and moldability, characterized by blending a nonionic surfactant with an LB value of about 18 or less.

The starting materials for the nonionic surfactants that are internal mold release agents in the present invention are aliphatic monoamines, aliphatic polyamines, aliphatic alkanolamines, etc., which have at least one long-chain aliphatic hydrocarbon group. 12, especially preferably having only one long-chain aliphatic hydrocarbon group, these starting materials require a hydrogen atom or at least one hydroxyalkyl group bonded to at least one nitrogen atom to which the monoepoxide can be attached. . Preferred amines are RIR2)NH (R1: long chain aliphatic hydrocarbon group).

R2: aliphatic mono- or diamine represented by hydrogen atom, lower aminoalkyl group, or lower alkyl group)
It is an aliphatic alkanolamine represented by 1(R3)N -R-OH (R3: lower alkyl group, or hydroxyalkyl group the same as or different from -R4-OH, R4: lower alkylene group), and in particular R1-NH2 The long-chain aliphatic hydrocarbon group is preferably an aliphatic polyamine represented by carbon@8 to 30. Preferably 12-24. Particularly preferably 14 to 20, the saturated number is 1 to 6. R4
The lower alkylene group represented by the formula preferably has 2 to 6 carbon atoms.

The monoepoxide added to the above amines is mainly ethylene oxide, and it is particularly preferable that the monoepoxide consists essentially of ethylene oxide.Other epoxides include alkylene oxides such as propylene oxide,
Examples include halogen-containing alkylene oxides such as epichlorohydrin, and styrene oxides. These monoepoxides other than ethylene oxide may be used in small amounts relative to ethylene oxide, and in that case, they can be mixed with other than ethylene oxide and added, or they can be added sequentially with ethylene oxide. The amount of ethylene oxide added is related to the HLB value described below. For example, taking the aliphatic monoamine represented by R1-NH2 above as an example, if R1 does not change, the HLB value increases as the amount of ethylene oxide added increases. Furthermore, if the amount of ethylene oxide added is the same, the HLB value generally decreases as the number of R1 carbon atoms increases. Therefore, the amount of ethylene oxide added is determined by the HLB value of the compound obtained. In addition, when other epoxides, particularly alkylene oxides other than ethylene oxide, are used in combination, the HLB value generally decreases as the proportion increases.

For example, in the monoepoxide adduct of the present invention obtained by adding only ethylene oxide, that is, the nonionic surfactant, the hydrogen atom of the hydroxyl group of the hydroxyalkyl group bonded to the nitrogen atom is -(C2H40)n-H. It is a substituted compound, for example, in the case of R1-NH2, R1-[(C2H40)k
H] is a compound represented by [(C2Ha 0) 1-H] (n, i, iL: integer, however, the average value is not necessarily an integer) The HLB value of the nonionic surfactant in the present invention is approximately 1
It must be 8 or less. The HLB value in nonionic surfactants is a well-known concept that indicates the balance between lipophilicity and hydrophilicity of the surfactant. J (A small LB value indicates high lipophilicity, and a large HLB value indicates high hydrophilicity. When lipophilicity and woodphilicity are almost balanced, the HLB value is approximately 12 to 14. If the nonionic surfactant has only long-chain alkyl groups and polyoxyethylene groups, the HLB value is (number of added moles of oxyethylene groups)/number of carbon atoms of long-chain alkyl groups). It is said to be proportional. However, if it has other lipophilic groups or hydrophilic groups, the value expressed by this formula and )HLB
It cannot be said that the valence is necessarily in a proportional relationship, and the same is true for the nonionic surfactant having a nitrogen atom or the like in the present invention. However, in the present invention, approximately 11 L
The B value and the value expressed by the above formula are in a proportional relationship.0 The HLB value of the nonionic surfactant in the present invention is about 18 or less, preferably about 17 or less, and the lower limit is about 6. is preferred.

The amount of HLB value of the nonionic surfactant used in the present invention is not particularly limited, but is suitably 0.1 to 10 parts by weight per 100 parts by weight of the high molecular weight active hydrogen-containing compound. 0.5 to 5 parts by weight is preferred. The nonionic surfactant in the present invention has at least one active hydrogen, particularly at least 1 hydroxyl group, as is clear from its structure. Therefore, it is reactive with isocyanate groups, and it is difficult to use it by mixing it with a polyisocyanate compound in advance.Therefore, it is preferable to use this nonionic surfactant by blending it with an active hydrogen-containing compound. In zero-reaction injection molding in which a high molecular weight polyol is suitable as the active hydrogen-containing compound, it can also be directly blended into the active hydrogen-containing compound-containing component described below.

The reaction injection molding method is the most preferred method for producing the polyurethane elastomer of the present invention, but it is not limited to this, and is applicable to other methods for producing polyurethane elastomers such as the one-shot method, prepolymer method, quasi-prepolymer method, etc. I can do it. However, the problem of moldability is a problem specific to molding methods that use molds, and is therefore not related to manufacturing methods that do not use molds. This does not include application to methods of molding, etc.

This is because the nonionic surfactant reacts with the incyanate group and is chemically bonded to the polyurethane elastomer, which is thought to be important in preventing it from leaching to the surface. In this respect, it is considered that blending into a pre-manufactured polyurethane elastomer that does not contain incyanate groups is not effective.

Accordingly, the present invention requires the presence of the nonionic surfactant in a reactive mixture in which free incyanate groups are present in reaction injection molding or other processes. Also, the use of an internal mold release agent in the present invention does not obviate the need for the combined use of an external mold release agent. It is necessary to use an external mold release agent, and even if a mold without an external mold release agent is used, good mold release properties cannot be achieved. can be used,
For example, a wax-based external mold release agent, a silicon-based external mold release agent, a fluorine compound external mold release agent, etc. can be used.

In the present invention, the reactive mixture is a mixture of at least two components, an active hydrogen-containing compound and a polyisocyanate compound.1 It usually further contains a catalyst, and it usually also contains a blowing agent and all other raw materials for the polyurethane elastomer. In zero-reaction injection molding, which is a mixture containing
It is a mixture of two components: a component usually called system liquid, which is a mixture of active hydrogen-containing compounds and all JPN components other than polyincyanate compounds, and a component containing polyisocyanate compounds, and is mixed by a mixing injection device called a high-pressure foamer. In the 6-reactive mixture, which is a reactive mixture that is injected, some or all of the components that are reactive with incyanate groups, such as reinforcing fibers and powder fillers, are blended with the incyanate compound. Sometimes. Further, it may be used as part or all of a polyisocyanate compound obtained by reacting a part of a high molecular weight polyol with a polyisocyanate compound in advance. It is also possible to carry out injection molding of two or more active hydrogen-containing compound components or polyisocyanate compound-containing components.

In the present invention, preferred compounds as high molecular weight active hydrogen-containing compounds are high molecular weight polyols, particularly polyoxyalkylene polyols, but are not limited thereto. For example, some or all of the hydroxyl groups of high molecular weight polyoxyalkylene polyols are It is known to produce polyurethane elastomers by reaction injection molding using aminated polyethers in which amine groups are substituted.
In the present invention, similar aminated polyethers can be used as part or all of the high molecular weight active hydrogen-containing compound. The aminated polyol preferably has a molecular weight in the same range as the high molecular weight polyol described below, and the amination rate is #JJ of all amino groups when used alone or in combination with a high molecular weight polyol.
/ (several tens of total amino groups, total number of hydroxyl groups), approximately (8
0% or less is appropriate.

In the present invention, high molecular weight polyol means an average molecular weight per hydroxyl group of about 800 to 4000. Approximately 1000~25 for a male
00. High molecular weight polyols consisting of one type or a mixture of two or more types having an average number of hydroxyl groups per molecule of 1.8 to 8.0, particularly about 2.0 to 3.5, are suitable. The high molecular weight polyol is particularly preferably a polyoxyalkylene polyol or a high molecular weight polyol mixture containing it as a main component.Other than polyoxyalkylene polyol, examples include hydroxyl hydrocarbon polymers such as polybutadiene glycol, and polyester polyol.

There are polyether ester polyols, polycarbonate polyols, etc. These can be used alone, but it is preferable to use them together with polyoxyalkylene polyols. When using polyoxyalkylene polyols and other high molecular weight polyols together, both The polyoxyalkylene polyol is at least 60% by weight to at least 80% by weight of the mixture! The other high molecular weight polyol used in combination is preferably at least 2% by weight.
Homopolymers and copolymers of butadiene having 2 hydroxyl groups are particularly preferred. Polyoxyalkylene polyols include polyoxyalkylene polyols selected by adding a large number of epoxides such as alkylene oxide to a polyvalent initiator, and 4-membered polyoxyalkylene polyols such as tetrahydrofuran. Ring-opened polymers of cyclic or larger cyclic ethers are suitable. Suitable polyhydric initiators include polyhydric alcohols, polyhydric phenols, alkanolamines, mono- and polyamines, and polyhydric alcohols are particularly preferred.As epoxides, fullylene oxide having 2 to 4 carbon atoms is most preferred. However, halogen-containing alkylene oxides, styrene oxides, glycidyl ethers, and other epoxides can be used in combination therewith. The most preferred polyoxyalkylene polyol is a polyoxyalkylene polyol obtained by adding propylene oxide as a polyvalent initiator, butylene oxide, particularly preferably propylene oxide, and ethylene oxide.

Ethylene oxide is preferably reacted in the last step of the addition reaction in order to have an oxyethylene group present at the end of the oxyalkylene chain of the polyoxyalkylene polyol. In some cases, ethylene oxide and other fullkylene oxides are mixed. The proportion of oxyethylene groups present in the terminal parts of the oxyalkylene chain is preferably at least 5% by weight; More preferably, it is about 8% by weight or more. In addition, the upper limit of the proportion of all oxy-diethylene groups is preferably 35% by weight or less. In particular, since terminal oxyethylene groups are necessary to ensure reactivity, oxyethylene groups in polyoxyalkylene polyols are required. Preferably, substantially all of is present at the terminal portion of the oxyalkylene chain.

The preferred average number of hydroxyl groups in the above polyoxyalkylene polyol is about 2.1 to 3.0.

This polyoxyalkylene polyol consists of a mixture of polyoxyalkylene triol or polyoxyalkylene diol and polyoxyalkylene polyol having a valence of 3 or more. The mixture of polyoxyalkylene polyols may be obtained by mixing separately produced polyoxyalkylene polyols, or by adding alkylenoxide or the like to a mixture of two or more types of polyvalent initiators. Examples of multivalent initiators that may be used in J-formation include, but are not limited to, the following compounds.

Polyhydric alcohols; polyethylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, polypropylene glycols such as dipropylene glycol, glycerin, trimethylolpropane, hexanetriol, pentaerythritol, diglycerin, dextrose, α- Methylglylocyto, nrubitol, sucrose.

Polyhydric phenols; bisphenol A, bisphenol S
l Catechol, phenol formaldehyde initial condensate.

Alkanolamine; monoethanolamine, jetanolamine, 1-liethanolamine, diisopanolamine, N-methyljetanolamine.

Mono- or polyamines; ethylenediamine, diethylenetriamine, diaminodiphenylmethane, aniline.

The chain extender is molecule I! It consists of a low molecular weight polyol and/or polyamine compound having a weight of L400 or less. In particular, low molecular weight polyols with a molecular weight of 200 or less are preferred.Low molecular weight polyols include polyhydric alcohols and alkanolamines having 2 or more hydroxyl groups, particularly 2 to 4 hydroxyl groups, and polyhydric initiators such as those described above, with a small amount of flukirexite added. Polyols obtained by

Particularly preferred low molecular weight polyols are dihydric alcohols having 2 to 4 carbon atoms. Suitable polyamines are aromatic diamines having alkylene substituents and/or halogens. A preferred specific chain extender is ethylene glycol.

1.4-butanediol, propylene glycol.

These include diethylene glycol, dipropylene glycol, glycerol 1-trimethylolpropane, jetanolamine, triethanolamine, etc. Ethylene glycol and 1,4-butanediol are particularly preferred. As the aromatic diamine, for example, diethyltoluene diamine, monochloroparaphenylene diamine, tetramethylmethylene dianiline, etc. are preferable, and the amount used is 1% to 40% by weight based on the total amount with the high molecular weight polyol.
Weight is 0-30%.

The polyincyanate compound consists of aromatic, alicyclic, aliphatic, and other polyisocyanate compounds having at least two incyanate groups, and modified products thereof. For example, 2.4-) lylene diisocyanate, 2. [1-
) lylene diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenylisocyanate, xylylene diisocyanate, inphorone diisocyanate, methylene-bis(cyclohexyl isocyanate, hexamethylene isocyanate, etc.). There are polyisocyanate compounds, trimers, prepolymer-type modified products, carbodiimide-modified products, urea-modified products, and others.These polyisocyanate compounds may be used in combination with 21i or more, and particularly preferred polyisocyanate compounds are 4.4 '-diphenylmethane diisocyanate, and its carbodiimide-modified products and prepolymer-type modified products.

The amount of the polyincyanate compound used is 80 to 120, particularly 85 to 110, expressed as incyanate index.
is appropriate.

In the production of polyurethane elastomers using the reaction injection molding method, it is essential to use a catalyst in addition to the above-mentioned main raw materials, and blowing agents include catalysts and organometallic compounds such as organotin compounds, and both may be used alone or in combination. 6 In the present invention, a blowing agent is not necessarily essential, and even without using a blowing agent, a slightly foamed elastomer can be obtained due to the presence of air and water dissolved in the raw materials.
Moreover, by sufficiently removing these, a non-foamed elastomer can be obtained.

However, it is preferable to use a small amount of blowing agent for reasons such as improving moldability. Air, water, etc. can be used as the blowing agent, but halogen hydrocarbons with a low boiling point are preferably used. Specifically, trichlorofluoromethane, diku-L
+rofluoromethane, iM-modified methylene, etc. are suitable. The amount is the sum of the high molecular weight polyol and the chain extender.
15 parts by weight or less, especially 2 to 1 to 0 parts by weight.

Parts by weight are appropriate.

Furthermore, various additives may be added as optional additive components. Examples include reinforcing fibers, fillers, colorants, ultraviolet absorbers, 4 antioxidants, flame retardants, and internal mold release agents. In particular, blending reinforced la fibers or flexible reinforcing agents has the effect of reducing the water absorption dimensional change rate. This is thought to be for improving the rigidity and strength of the polyurethane elastomer.As the 6-reinforced am, milled glass TA fiber, Chikara-nod fiber, or Wollastonai F is suitable. Moreover, mica glass flakes or the like can be used as the flake-like reinforcing agent. The amount is approximately 20% by weight based on the entire Boliu I, -tan elastomer.
The following effects are sufficient. These additives, including the catalysts and blowing agents mentioned above, are usually added to the polyol component containing the high molecular weight polyol and chain extender.

However, additives which are inert towards incyanate groups can also be added to the incyanate component. The sudden reaction injection molding method is usually carried out by rapidly mixing the polyol component and the incyanate component to form a reactive mixture, which is immediately injected into a mold and taken out as a molded sculpture.

In some cases, a polyol component or an incyanate component may be added.
Three or more components may be used by dividing them into the above components or by using a third component. Rapid mixing is usually achieved by impingement mixing of each component, and an after-mixing mechanism may be provided in a portion of the runner to perform remixing.

The present invention is used for molding exterior parts of automobiles, especially bumper shells. However, it is not limited to this use, and can be used for other automobile parts, molded products for housing,
It can also be applied to other uses.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

'Male side and comparative example A mixture of a high molecular weight polyol containing the internal mold release agent of the present invention, a chain extender, etc. was charged into the polyol component side tank of the high pressure foaming machine, and a mixture of a chain extender, etc. 150kg/crn', discharge amount 80-120
Reaction injection molding was carried out by adjusting the liquid temperature of each component to 30 to 40°0. The size of the mold is 140mm x 1
Molding was carried out by using an iron Venus for forming the outer shell of an automobile bumper, measuring 20+am x 1400mm and having an inner thickness of 3m+m, and adjusting the mold temperature to 60 to 70°C. Also, when molding, first apply a wax-based mold release agent to the mold, and then! 11 How many times could the molding force be measured without cloth? t the result
5+ Shown in the table.

Raw material polyol component High molecular weight polyol or high molecular weight polyol 100
Part by weight High molecular weight polyol A: Polyoxypropylenoxyethylene diol with a molecular weight of about 4000 and an oxyethylene group content of 20% by weight.

High molecular weight polyol B: polyoxypropylenoxyethylene triol with a molecular member of approximately 1350 (') and an oxyethylene group content of 15% by weight.

Chain extender: ethylene glycol 18 parts by weight Internal mold release agent (shown in Table 1) 1. Ott [In the table, (EO) is an oxyethylene group.

C02H40)] Incyanate component carbodiimide-modified diphenylmethane diincyanate)
(1100 go IJ! c28%) The amount of L used is ffi with an index of 105] External molding agent (wax type) B-2630 (manufactured by Middle East Oil ■): Examples 1 to 4, and comparative example D-18 [ 1 (tt): Examples 5-6 1st Table ÷ 1 River ■ j Procedural correction @: (Method) % formula % 2, Invention name + j, Boriutta, System error 7 To 7 ~
Manufacturing method 3, relationship with the person making the supplement “j1-11”
i Chiyo, Tokyo) 1-ku Marunouchi 2-1-2゛shi 4.
Zangetsu 1 person 111゛ha Higashijj! Torano 11gawa-1'll, Buminato-ku]6
No. 2 Bow The full text of the 7th amendment The content specification of the 8th amendment will be corrected as shown in the attached sheet.

(No change in content)

Claims (1)

[Claims] 1. A reactive mixture of a polyisocyanate compound and a high molecular weight active hydrogen-containing compound and a chain extender is cured in a mold to form a non-foamed or micro-containing compound. In a method for producing a cellular polyurethane elastomer, a reactive mixture having an HLB value of about 18 or less and consisting of a monoepoxide adduct mainly containing ethylene oxide of amines or alkanolamines having a long-chain aliphatic hydrocarbon group is used. A method for producing a polyurethane elastomer having internal sales properties, which comprises blending a nonionic surfactant. 2. The method according to claim 1, characterized in that a nonionic surfactant is blended in advance with the active hydrogen-containing compound. 3. Amines with long chain aliphatic hydrocarbon groups have 12 carbon atoms
24. The method of claim 1, wherein the aliphatic monoamine is an aliphatic monoamine of ~24. 4. The method according to claim 1, wherein the method for manufacturing the polyurethane elastomer is a reaction injection molding method.