JP2008111039A - Thermosetting polyurethane resin composition and its molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting polyurethane-based resin composition effectively utilizing the cured polyurethane resin while retaining a characteristic (mechanical strength or the like) of the thermosetting polyurethane-based resin. <P>SOLUTION: The thermosetting polyurethane-based resin composition is constituted by a thermosetting polyurethane-based resin (A) (for example, a reaction product of an aromatic diisocyanate and a polymer polyol or the like), and a fine (for example, average particle diameter of 500 μm or less) cured polyurethane-based resin (B). A ratio of the polyurethane-based resin (B) may be usually 25 pts.wt. or less based on 100 pts.wt. of the polyurethane-based resin (A) in order to sufficiently retain moldability (cast moldability or the like) and a treating property of the resin composition. The polyurethane-based resin (B) may be constituted by a waste polyurethane-based resin such as a resin chip produced in cast molding of the thermosetting polyurethane-based resin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thermosetting polyurethane resin composition (or thermosetting polyurethane elastomer composition) capable of effectively using a cured polyurethane resin, a molded product thereof (particularly a cast molded product), and a manufacturing method thereof (cast molded product). Manufacturing method).

  Polyurethane resin molded products are superior in abrasion resistance, mechanical properties, dynamic physical properties, solvent resistance, oil resistance, ozone resistance, etc. compared to general elastomer compositions. In addition to industrial parts such as belts, rolls and casters, office automation (OA) equipment parts such as paper feed rolls and copier rolls, it is used in a wide range of fields such as sports and leisure goods.

  Such a polyurethane resin molded article is casted, for example, a mixture of a urethane prepolymer having an NCO group (isocyanate group) at the end and a chain extender is injected into the mold and cured for a predetermined time, followed by demolding. It is manufactured by the method to do. In such a casting method, after the casting, a protruding waste of the thermosetting polyurethane resin cured around the mold is generated. Thus, the cured polyurethane resin (polyurethane waste) usually has a problem that it cannot be used as a product and is also expensive to dispose of.

  As an example of reusing a cured polyurethane resin, JP 2000-226524 A (Patent Document 1) discloses a waste urethane refinement obtained by refining a polyurethane waste after thermosetting, a thermoplastic resin ( (Nylon resin, polystyrene resin, polypropylene resin, polyethylene resin, vinyl chloride resin, polyethylene butyrate resin, polyethylene terephthalate resin, polycarbonate resin, etc.) are blended at a ratio of 200 parts by weight or less with respect to 100 parts by weight. A thermoplastic resin composition is disclosed. In this document, waste urethane refinement refers to various products that use rigid polyurethane foam, such as polyurethane waste that is discharged at the same time when refrigerators and automobiles become waste, and rigid polyurethane foam. It is described that polyurethane waste generated in the factory as a defective product in the manufacturing process of the finished product can be obtained by finely pulverizing by a home appliance recycling processing plant, a waste car processing recycling plant, etc. . Further, in this document, a thermoplastic resin, waste urethane refined product, an inorganic reinforcing filler to be blended as necessary, and other additives are blended at a predetermined ratio, and a single screw extruder for plastic kneading or It is described that the resin composition can be produced by uniformly kneading with a twin screw extruder.

As described above, in this document, the physical properties of the thermoplastic resin are improved by uniformly dispersing the polyurethane refined product in the thermoplastic resin using an extruder. In this document, the cured product is uniformly dispersed in a resin by using kneading, and the use of the polyurethane refined product is limited to the use as a filler of a thermoplastic resin that can be melt-kneaded.
JP 2000-226524 A (claims, paragraph numbers [0012] [0013] [0020])

  Accordingly, an object of the present invention is to provide a thermosetting polyurethane resin composition capable of effectively utilizing a cured polyurethane resin while maintaining the same properties (such as mechanical strength) of the thermosetting polyurethane resin, and the resin composition. The object is to provide a molded article formed of a product.

  Another object of the present invention is to provide a thermosetting polyurethane resin composition capable of reusing a cured polyurethane resin without impairing moldability (such as cast moldability) and a molded article formed from the resin composition. Is to provide.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have added a cured polyurethane resin (cured product of polyurethane resin) to a thermosetting polyurethane resin (or urethane prepolymer), The inventors have found that the properties (such as mechanical strength) of the thermosetting polyurethane resin molded product can be maintained at a practical level, and that a cured product of the polyurethane resin can be effectively reused, thereby completing the present invention.

  That is, the thermosetting polyurethane resin composition of the present invention comprises a thermosetting polyurethane resin (A) (or urethane prepolymer) and a granular (or fine) cured polyurethane resin (B). Has been. In such a resin composition, the ratio of the polyurethane resin (B) is sufficient to maintain the moldability (such as cast moldability) and the handleability of the resin composition. ) Normally, it may be 25 parts by weight or less per 100 parts by weight. The polyurethane resin (A) includes, for example, a reaction product (aromatic diisocyanate and an aromatic diisocyanate (for example, TDI, MDI, etc.) and a polymer polyol (for example, a polyether polyol such as polytetramethylene ether glycol). It may be a urethane prepolymer reacted with a polymer polyol.

  The polyurethane resin (B) only needs to be miniaturized, and may usually be in a powder form. For example, the polyurethane resin (B) may be a powdery polyurethane resin having an average particle diameter of 500 μm or less.

  In the resin composition of the present invention, the polyurethane resin (B) may be composed of a waste polyurethane resin (specifically, a waste of a cured product obtained by curing a thermosetting polyurethane resin). . In particular, the polyurethane-based resin (B) may be composed of resin waste (molded waste, cured resin waste) generated in molding (for example, cast molding) of a thermosetting polyurethane-based resin. Usually, by using a waste polyurethane resin that is difficult to reuse, not only waste plastic processing costs but also cost reduction of raw materials can be realized.

  In the typical resin composition of the present invention, (1) the polyurethane resin (A) comprises at least one aromatic diisocyanate selected from arene diisocyanates and diphenylalkane diisocyanates and a polyether polyol. (2) The polyurethane resin (B) is a pulverized resin waste produced in the casting of a thermosetting polyurethane resin, and has a mean particle size of 500 μm or less. A resin composition in which the proportion of (3) polyurethane resin (B) is 1 to 25 parts by weight with respect to 100 parts by weight of polyurethane resin (A) is included.

The resin composition of the present invention may further contain a curing agent. Such a curing agent is at least selected from amine-based curing agents (for example, bis (aminophenyl) alkanes (such as MOCA) and alcohol-based curing agents (for example, low molecular polyols such as C _2-6 alkanediol). You may comprise by 1 type.

  The present invention also includes a molded article (or a cured product obtained by curing the resin composition) formed of the thermosetting polyurethane resin composition. Such a molded product (or molded product) may be a cast molded product. The resin composition of the present invention can sufficiently retain the properties (such as mechanical strength) of a molded product even when a molding method that does not involve kneading such as cast molding is applied. Further, the present invention includes a method of casting the resin composition to produce a cast molded product. In such a manufacturing method, for example, a mixture in which a thermosetting polyurethane resin (A) and a granular cured polyurethane resin (B) are mixed in advance may be poured into a mold and cast. .

  In the thermosetting polyurethane resin composition of the present invention, the properties (such as mechanical properties) of the molded product can be maintained at a practical level even when a cured polyurethane resin is added to the thermosetting polyurethane resin. Therefore, the cured polyurethane resin can be effectively used while maintaining the same characteristics (such as mechanical strength) of the thermosetting polyurethane resin. In particular, when waste polyurethane resin is used as the cured polyurethane resin, waste material processing costs and compounding material costs can be reduced while maintaining the properties of the molded product at the same level as conventional molded products. Is also advantageous. In the resin composition of the present invention, the cured polyurethane resin can be reused without impairing moldability (such as cast moldability) by adding a cured polyurethane resin at a specific ratio.

  The thermosetting polyurethane resin composition of the present invention is composed of a thermosetting polyurethane resin (A) and a cured polyurethane resin (B).

[Polyurethane resin (A)]
The thermosetting polyurethane resin (A) (simply referred to simply as thermosetting polyurethane resin, polyurethane resin (A), resin (A), etc.) is a compound having an isocyanate group at the terminal, that is, isocyanate at the terminal. It is a prepolymer having a nate group (urethane prepolymer). Such a thermosetting polyurethane resin (urethane prepolymer) may usually be a reaction product of a polyisocyanate component and a polyol (particularly polymer polyol) component.

(Polyisocyanate component)
It does not specifically limit as a polyisocyanate component, For example, polyisocyanate, such as aromatic polyisocyanate, araliphatic polyisocyanate, alicyclic polyisocyanate, aliphatic polyisocyanate, is mentioned.

Aromatic polyisocyanates include, for example, arene diisocyanates {for example, phenylene diisocyanate, 1,5-naphthalene diisocyanate (NDI), tolylene diisocyanate (TDI) (2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate , Mixtures thereof, etc.), substituents such as 2-chloro-1,4-phenylene diisocyanate [halogen atom (bromine atom, chlorine atom, fluorine atom, etc.), alkoxy group (for example, linear or branched such as methoxy group) A linear C _1-6 alkoxy group), an alkyl group (for example, a linear or branched C _1-6 alkyl group such as a methyl group), and the like hereinafter, the same in the description of the substituent of the polyisocyanate]. which may be arene diisocyanate (for _{example, C 6-14} array Down - diisocyanate, preferably _{C 6-12} arene - diisocyanate), etc.}, diaryl diisocyanates (e.g., 4,4'-diphenyl diisocyanate, 3,3'-dimethyl-4,4'-diphenyl diisocyanate, 3,3 ' -Diphenyl diisocyanates such as dimethoxy-4,4'-diphenyl diisocyanate), diarylalkane diisocyanates [e.g. diphenylmethane diisocyanate (MDI) (e.g. 4,4'-, 2,4'- or 2,2'- Diphenylmethane diisocyanate, mixtures thereof, etc.), 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate (tolidine diisocyanate, TODI), 3,3′-dimethoxy-4,4′-diphenylmethane diisocyanate, 2,2 Bis (4-isocyanatophenyl) diphenylalkane diisocyanates such as propane (e.g., which may have a substituent diphenyl _{C 1-10} alkane - diisocyanate, preferably diphenyl _{C 1-6} alkane - Jiisoianeto), etc.], Diaryl ether diisocyanates (for example, diphenyl ether diisocyanates such as 4,4′-diphenyl ether diisocyanate), di (isocyanatoaryl) sulfides (for example, di (isocyanatophenyl) sulfide such as bis (4-isocyanatophenyl) sulfide ), Di (isocyanatoaryl) ketones (for example, di (isocyanatophenyl) ketones such as 4,4′-diphenylketone diisocyanate), di (isocyanatoaryl) sulfone (For example, aromatic diisocyanates such as di (isocyanatophenyl) sulfones such as 4,4′-diphenylsulfone diisocyanate), trifunctional or higher functional polyisocyanates (for example, aromatic triisocyanates such as triphenylmethane triisocyanate) Etc.).

  Examples of the araliphatic polyisocyanates include fragrances such as di (isocyanatoalkyl) arenes [for example, di (isocyanatoalkyl) benzenes such as xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI)]. Aliphatic diisocyanate and the like can be mentioned.

As the alicyclic polyisocyanate, cycloalkane diisocyanates (for example, cyclopentane diisocyanate, cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate and the like have a substituent. C _5-8 cycloalkane-diisocyanate), isocyanatoalkylcycloalkane isocyanates (eg, isophorone diisocyanate (IPDI)), di (isocyanatocycloalkyl) alkanes (eg, dicyclohexylmethane diisocyanate (hydrogenated MDI) ) which may bis have a substituent such as (isocyanato _{C 5-10 cycloalkyl) C 1-10} alkanes), di (isocyanatomethyl alkyl) cycloalkanes example If, bis (isocyanatomethyl) cyclohexane, alicyclic diisocyanates such as may have a substituent group, such as hydrogenated TODI di (isocyanato _{C 1-6 alkyl) C 5-10} cycloalkane, trifunctional or higher And alicyclic polyisocyanates (for example, alicyclic triisocyanates such as 1,3,5-triisocyanatocyclohexane, 1,3,5-trimethylisocyanatocyclohexane).

Examples of the aliphatic diisocyanate include alkane diisocyanates (C _2-20 alkane-diisocyanates such as hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, and trimethylhexamethylene diisocyanate), aliphatic diisocyanates such as lysine diisocyanate, and trifunctional or higher functional fats. Polyisocyanates (for example, aliphatic triisocyanates such as 1,4,8-triisocyanatooctane, 1,8-diisocyanate-4-isocyanatomethyloctane, 1,6,11-undecane triisocyanate) and the like. It is done.

  Preferred polyisocyanates include aromatic diisocyanates and alicyclic diisocyanates because of their excellent moldability and physical properties, and arene diisocyanates (such as TDI) and diphenylalkane diisocyanates (such as MDI). Etc. are preferable.

  These polyisocyanates can be used alone or in combination of two or more.

  The polyisocyanate component is a derivative of the polyisocyanate, for example, a multimer of the polyisocyanate monomer (a dimer, a trimer having an isocyanurate ring (triazine ring), a pentamer, etc.), a urethane-modified product, A biuret modified body, an allophanate modified body, a urea modified body, etc. may be sufficient. Such derivatives include, for example, MDI having an average functional group number of about 2 to 3, such as isocyanurate-modified MDI and polymeric MDI. These derivatives may be used alone or in combination of two or more, and may be used in combination with the polyisocyanate monomer.

(Polyol component)
As described above, the prepolymer having an isocyanate group at the terminal may be usually a reaction product of the polyisocyanate component and the polyol component. The polyol component may usually be a polymer polyol, such as a polyether-based polyol, a polyester-based polyol, or a polycarbonate-based polyol. These polyol components can be used alone or in combination of two or more.

Examples of the polyether-based polyol include, for example, alkylene oxide homo- or copolymers [ethylene or propylene oxide, butylene oxide, tetrahydrofuran, 3-methyltetrahydrofuran and other C _2-6 alkylene oxide homo- or copolymers (for example, Poly _C2-4 alkylene oxides such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and copolymers thereof (for example, polyethylene oxide-polypropylene oxide block copolymers, etc.) etc.], bisphenol A or water alkylene oxide adducts of hydrogenated bisphenol a (e.g., C _2-4 alkylene oxide 1-5 moles added adduct to the hydroxyl group) such as can be illustrated .

Examples of the polyester polyol include an aromatic dicarboxylic acid component (dicarboxylic acid such as isophthalic acid and terephthalic acid) and an aliphatic dicarboxylic acid (linear C _4-10 dicarboxylic acid such as adipic acid and sebacic acid). At least one dicarboxylic acid (or dialkyl ester thereof) and an alkanediol component (ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexane) Diol, C _2-10 alkane diol such as neopentyl glycol, di or tri C _2-10 alkane diol such as diethylene glycol, etc.). Preferred polyester polyols include dicarboxylic acid components such as adipic acid, terephthalic acid, terephthalic acid dialkyl ester, isophthalic acid, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, etc. This is a polyester polyol (or polyester diol) by reaction with alkanediol. More specifically, polyester diols based on adipic acid as a dicarboxylic acid component, such as polyethylene adipate (PEA), polydiethylene adipate (PDA), polypropylene adipate (PPA), polytetramethylene adipate ( PBA), polyhexamethylene adipate (PHMA), and a copolymer obtained by combining these components. Polyester polyols include homopolymers or copolymers (poly-ε-caprolactone) of lactones (C _3-14 lactones such as ε-caprolactone, δ-valerolactone, and β-methyl-δ-valerolactone). (PCL) etc.).

  As the polycarbonate-based polyol, for example, a polycarbonate diol obtained by a reaction between a polyol (the alkane polyol, the polyether-based polyol, the polyester-based polyol) and a short-chain dialkyl carbonate (for example, an alkyl carbonate such as dimethyl carbonate), for example, Examples thereof include polyhexamethylene carbonate (PHC).

  The molecular weight of the polyol component (polymer polyol) may be a number average molecular weight of 400 to 10000, preferably 500 to 8000, more preferably about 550 to 5000 (for example, 600 to 3000). The polymer polyol may be crystalline or non-crystalline.

  The terminal isocyanate group-containing prepolymer can be obtained by reacting an excess amount of the polyisocyanate component with respect to the polyol component. For example, the equivalent ratio of the isocyanate group of the polyisocyanate component to the hydroxyl group of the polyol component ( NCO / OH) may be 1.2 to 5, preferably 1.3 to 4 (for example, 1.4 to 3), and more preferably about 1.5 to 2.5.

  A preferred prepolymer is a reaction product of the polyisocyanate component [aromatic diisocyanate such as arene diisocyanates (such as TDI)] and a polymer polyol (for example, polyether polyol such as polytetramethylene ether glycol). Urethane prepolymer).

[Hardened polyurethane resin (B)]
The resin composition of the present invention contains a cured polyurethane resin (B) (cured product of thermosetting polyurethane resin). Such a resin composition can be dispersed with high dispersibility even if a cured polyurethane resin is added to a urethane prepolymer, which is a thermosetting resin, because it is a resin of the same type. For this reason, in spite of containing the hardened polyurethane-type resin, the characteristics (such as mechanical strength) of the thermosetting polyurethane-type resin molded product can be maintained as efficiently as the conventionally blended molded product. In particular, when a waste polyurethane resin is used as the resin (B), it is possible to reduce the cost for treating the waste material and the cost of the blended material, and it is environmentally advantageous.

  The polyurethane resin (B) may be a cured resin as described above, and may be prepared in advance for mixing with the polyurethane resin (A). A waste material of a base resin). When a waste polyurethane resin is used as the polyurethane resin (B), it is possible to effectively reuse waste plastics that conventionally required cost and labor for processing. Such a polyurethane-based resin (B) (waste polyurethane-based resin) may be a resin derived from a waste of an already molded polyurethane-based resin molded product, and the thermosetting polyurethane-based resin is cured (or You may comprise by the waste (molding waste, hardening resin waste) produced | generated in manufacture or a shaping | molding process. For example, the polyurethane-based resin (B) may be polyurethane-based resin waste generated in cast molding of a thermosetting polyurethane-based resin (or a composition thereof). In cast molding, protruding waste of a polyurethane resin cured product is generated around the mold, but in the present invention, polyurethane resin waste associated with such cast molding can be effectively reused.

  The shape of the polyurethane-based resin (B) is usually powdery. The shape of such a powdery polyurethane resin may be powdery (or powdery) or fibrous as long as it is powdery, and these shapes may be mixed. Usually, the polyurethane-based resin (B) may be in a powder form. The average particle size of the powdered polyurethane resin (B) can be selected from a range of 1000 μm or less (for example, about 1 to 700 μm), for example, 500 μm or less (for example, about 10 to 480 μm), preferably 450 μm or less (for example, , About 30 to 420 μm), more preferably 400 μm or less (for example, about 50 to 350 μm). Although powder having an average particle size of about 100 μm or less can be obtained by selecting a pulverizing means, a powdery polyurethane resin (B) having an average particle size of 300 μm or more (for example, about 350 to 500 μm) is preferable in terms of cost. May be used for

  The fine polyurethane resin (B) may be a crushed product (or crushed product) of a cured polyurethane resin (cured product of a thermosetting polyurethane resin). Such a crushed material can be obtained by crushing (or crushing) a cured polyurethane resin. The pulverization treatment is not particularly limited, but may be performed using a pulverizer (screw mill, roll mill, disintegrator, etc.). Further, after preliminary pulverization, the final particle size may be pulverized.

  As long as the polyurethane resin (B) is an already cured polyurethane resin, the type of the thermosetting polyurethane resin (urethane prepolymer) that is a raw material before curing is not particularly limited. Examples of the thermosetting polyurethane resin that is a raw material of the polyurethane resin (B) include the same compounds (urethane prepolymers) as described in the section of the polyurethane resin (A). The types and ratios of the components (polyisocyanate component, polyol component, etc.) can be selected from the same range as described above.

  The polyurethane resin (B) is usually a cured product obtained by curing a urethane prepolymer with a curing agent, but the type of the curing agent is not particularly limited. Examples of the curing agent include a curing agent described later (such as an amine-based curing agent), and the usage ratio can be selected from the same range.

From the viewpoint of maintaining the mechanical strength of the cured polyurethane resin, a relatively hard cured polyurethane resin may be used. The polyurethane resin (B) includes a urethane prepolymer having an aromatic polyisocyanate as a polyisocyanate component [for example, an aromatic polyisocyanate (arene diisocyanate, diphenylalkane diisocyanate, etc.) and a polyether polyol (polyester). C _2-4 alkylene oxide, etc.) and a cured product obtained by curing a thermosetting polyurethane-based resin composition containing at least a curing agent composed of an aromatic diamine. In particular, the polyurethane-based resin (B) may be a cured product obtained by curing a polyurethane-based resin (or a composition thereof) of the same or the same type as the thermosetting polyurethane-based resin (A).

  The proportion of the polyurethane resin (B) is usually 25 parts by weight or less (for example, about 0.1 to 23 parts by weight, preferably about 0.5 to 22 parts by weight with respect to 100 parts by weight of the polyurethane resin (A). ), Preferably 20 parts by weight or less (for example, about 1 to 18 parts by weight), more preferably about 2 to 15 parts by weight (for example, 3 to 12 parts by weight). When the polyurethane-based resin (B) is used within the above range, the viscosity of the urethane prepolymer is not extremely increased particularly in the casting, so that the moldability (or handleability) is maintained and the efficiency is improved. The polyurethane resin (A) can be cured. If the proportion of the polyurethane resin (B) used is too large, the viscosity of the urethane prepolymer solution will greatly increase, and the fluidity of the solution will drop when poured into a mold, and heat will flow before flowing into the mold. Curing may occur.

[Curing agent]
The resin composition of the present invention may usually further contain a curing agent for curing the thermosetting polyurethane resin (urethane prepolymer).

  The curing agent (or crosslinking agent or chain extender or chain extender) is not particularly limited, and examples thereof include amine-based curing agents (amine-based compounds), alcohol-based curing agents, isocyanate-based curing agents (such as the polyisocyanates illustrated above). Polyisocyanate compounds, etc.), epoxy curing agents (polyepoxy compounds), amino resin curing agents (melamine compounds, guanamine compounds, etc.), dihydrazide curing agents, carbodiimide curing agents, oxazoline curing agents, aziridine curing agents Etc. These hardening | curing agents can be used individually or in combination of 2 or more types.

Examples of amine curing agents include diamines {for example, alkane diamines (for example, ethylene diamine, propylene diamine, hexamethylene diamine, 1,2-diaminoethane, 1,2-diaminopropane, 1,3-diaminopentane, 1, Aliphatic diamines such as C _1-10 alkanediamines such as 6-diaminohexane); diaminoarenes (eg, diamino C _6-10 arenes such as m-phenylenediamine, diaminotoluene), bis (aminoaryl) alkanes [For example, bis- (4-aminophenyl) methane, bis- (4-amino-3-chlorophenyl) methane (or 3,3′-dichloro-4,4′-diaminodiphenylmethane or methylenebis (2-chloroaniline)] , MOCA) and other bis (aminophenyl) alka Aromatic diamines (or aromatics such as bis (aminophenyl) C _1-10 alkane, preferably bis (aminophenyl) C _1-6 alkane, etc.) Low molecular weight diamines such as diamines having a skeleton} and polyamines having three or more amino groups (for example, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, 2,2′-diaminodiethylamine, etc.) Polyamines such as molecular weight polyamines; alkanolamines (ethanolamine, diethanolamine, etc.); aminobenzoate-based curing agents [eg, alkylenebis (aminobenzoate) s (eg, C, such as trimethylenebis (4-aminobenzoate), etc. _2-6 alkylene bis (Such as aminobenzoate), polyalkylene oxide-bis (aminobenzoate) (eg, poly C _2-6 alkylene oxide-bis (aminobenzoate) such as polytetramethylene oxide-di-p-aminobenzoate), etc.] Etc. Aminobenzoate-based curing agents can also be obtained from Ihara Chemical Industry Co., Ltd. as “Elastomer” series. Amine curing agents may be used alone or in combination of two or more.

As the alcohol-based curing agent (polyhydric alcohol-based curing agent), diols, polyols having 3 or more (for example, about 3 to 8) hydroxyl groups in the molecule (particularly low molecular compounds), and the like can be used. Examples of the diol include alkane diols (C _2-10 alkane diols such as ethylene glycol, propylene glycol, 1,4-butane diol, pentane diol, and hexane diol, preferably C _2-6 alkane diols, more preferably C _{2− 4-} alkanediol), di- or trialkanediol (eg, diethylene glycol, triethylene glycol, etc.), bisphenols (eg, bisphenol A), or hydrogenated bisphenols (eg, hydrogenated bisphenol A), and alkylene oxide adducts. . Examples of the polyols include triols (glycerin, trimethylolethane, trimethylolpropane, alkanetriols such as hexanetriol, triethanolamine, etc.), tetraols (for example, pentaerythritol, diglycerin, methylgluol). Examples thereof include cogits), pentaols (such as xylitol), hexaols (such as sorbitol, mannitol, dipentaerythritol), octools (such as sucrose), and the like. Moreover, about 1-2 mol _C2-4 alkylene oxide (ethylene oxide etc.) may add with respect to the hydroxyl group of these compounds. Furthermore, as the alcohol-based curing agent, for example, C _2-4 alkylene oxide adducts of alkylene diamine (ethylene oxide adducts of C _2-6 alkylene diamine such as ethylene diamine and propylene diamine) and the like can be used. These alcoholic curing agents can be used alone or in combination of two or more.

  The molecular weight of the alcohol-based curing agent (polyhydric alcohol) may be, for example, about 60 to 350, preferably about 70 to 300, and more preferably about 80 to 250 (for example, 85 to 200).

  Preferred curing agents include amine curing agents, alcohol curing agents and the like. In particular, the curing agent may be composed of at least an amine-based curing agent [for example, aromatic diamines such as bis (aminophenyl) alkanes (such as MOCA)].

  When combining an amine curing agent with another curing agent (for example, an alcohol curing agent), the ratio of the other curing agent (particularly, the alcohol curing agent) to the entire curing agent is 1 to 50 mol% (for example, 2 to 40 mol%), preferably 3 to 35 mol% (for example, 5 to 30 mol%), more preferably about 5 to 25 mol% (for example, 8 to 20 mol%).

  The ratio of the curing agent (for example, the amine curing agent alone, the amine curing agent and the alcohol curing agent) to the prepolymer is, for example, the active hydrogen atom (for example, amino group) of the curing agent with respect to the isocyanate group of the prepolymer. Group hydrogen atom, amino group hydrogen atom and hydroxyl group hydrogen atom) 0.7 to 1.2 equivalents, preferably 0.8 to 1.1 equivalents, more preferably about 0.9 to 1.0 equivalents. There may be.

  The resin composition of the present invention may contain a catalyst for adjusting the curing reaction (for example, an amine catalyst, a tin catalyst such as dibutyltin dilaurate). Furthermore, various additives as necessary, for example, release agents, antifoaming agents (silicone oil, modified silicone oils, etc.), surfactants (nonionic surfactants, etc.), stabilizers (antioxidants, UV absorbers, etc.) ), Flame retardants, antistatic agents, plasticizers, fillers, colorants, and the like.

  The resin composition of the present invention is effective for producing a polyurethane elastomer. Since the resin composition of the present invention combines a thermosetting polyurethane resin and a cured polyurethane resin, the dispersibility of the polyurethane resin after curing is good and can be molded by various molding methods. Even if a molding method without kneading, such as cast molding, is applied, the properties (mechanical properties) of the molded body (cured product) can be maintained as efficiently as when the cured polyurethane resin is not included. . The cast molded product can be produced by cast molding the resin composition of the present invention. Cast molding is a conventional prepolymer method. For example, a urethane prepolymer and a curing agent are heated as necessary, and after mixing the prepolymer and the curing agent, the mixture is poured into a predetermined mold and heated and cured. It can be performed by releasing the mold and post-curing if necessary. In such cast molding, the cured polyurethane resin may be mixed in advance with a prepolymer and / or a curing agent, or may be mixed with a mixture of a prepolymer and a curing agent. From the viewpoint of enhancing the dispersibility of the cured polyurethane resin, the urethane prepolymer and the cured polyurethane resin may be mixed in advance, and then the obtained mixture and the curing agent may be mixed. For example, a mixture in which a thermosetting polyurethane resin (A) and a fine cured polyurethane resin (B) are mixed in advance may be poured into a mold and cast.

  Molded articles (particularly cast molded articles) formed of the resin composition of the present invention have various uses such as belts (general industrial power transmission belts, etc.), rolls, tires (casters). (Including tires), guide rolls, pulleys, rubber screens, gears, copying machine cleaning blades, rollers, etc.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

(Examples 1-4 and Comparative Examples 1-4)
The main raw material liquid prepared by mixing the components shown in the table and the curing agent liquid shown in the table are each heated and mixed at a predetermined temperature (main raw material liquid: 60 ° C., curing agent liquid: 120 ° C.), Vacuum degassed. The mixed liquid after vacuum degassing was poured into a mold (90 mm × 110 mm × 2 mm) heated to 115 ° C. previously coated with a release agent and cured for a predetermined time to obtain a molded body.

  After the obtained molded body was aged at 60 ° C. for 24 hours, the physical properties were measured according to JIS standards (JIS-K6251 and JIS-K6254).

  In addition, the material used in the Example and the comparative example is shown below.

[Urethane prepolymer]
Coronate 4095 (Nippon Polyurethane Co., Ltd., NCO content: 6.3%, prepolymer obtained by reaction of tolylene diisocyanate and polytetramethylene ether glycol)
Coronate 4370 (Nippon Polyurethane Co., Ltd., NCO content: 15.0%, prepolymer obtained by reaction of diphenylmethane diisocyanate with polytetramethylene ether glycol)
[Hardened polyurethane powder]
When the molded body (cured product) was molded in Comparative Example 3 of Table 1 as the cured polyurethane, the protruding waste protruding from the mold was used. After the extruding waste was preliminarily pulverized to a particle size of about 10 mm with a crusher (manufactured by Horai Co., Ltd., “SR-360”, mesh diameter: 6 × 12 mm), By pulverizing with “HA-2542” manufactured by Horai Co., Ltd., mesh diameter: 0.5 × 0.5 mm, a powdery product having an average particle size of 500 μm or less (particle size 350 to 500 μm) is obtained. This powder was used as urethane powder.

[Plasticizer]
Phthalic acid derivative (manufactured by Shin Nippon Chemical Co., Ltd., Sunsocizer C-1100)
[Defoaming agent]
Silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KS-66)
[Curing agent]
Amine-based curing agent (methylenebis (2-chloroaniline) (MOCA), manufactured by Ihara Chemical Co., Ltd., “Iharacamine MT”)
Alcohol-based curing agent (1,4-butanediol, manufactured by Tosoh Corporation)
The results are shown in Table 1 together with the ratio of each component in Examples and Comparative Examples. The kinematic viscosity at 60 ° C. of the main raw material liquid was measured using a BP viscometer (manufactured by Tohnichi Seisakusho).

  As can be seen from the table, in the examples, it was possible to obtain a molded product having the same mechanical properties as the molded product not containing polyurethane waste. In particular, in Examples, cast molding was possible while suppressing an increase in kinematic viscosity of the main raw material liquid, and a molded body could be obtained without impairing moldability.

Claims (10)

  It is composed of a thermosetting polyurethane resin (A) and a granular cured polyurethane resin (B), and the proportion of the polyurethane resin (B) is 100 parts by weight of the polyurethane resin (A). A thermosetting polyurethane resin composition that is 25 parts by weight or less.   The resin composition according to claim 1, wherein the polyurethane resin (A) is a reaction product of an aromatic diisocyanate and a polymer polyol.   The resin composition according to claim 1, wherein the polyurethane resin (B) is a powdery polyurethane resin having an average particle size of 500 µm or less.   The resin composition according to claim 1, wherein the polyurethane resin (B) is composed of a waste polyurethane resin.   The resin composition according to claim 1, wherein the polyurethane-based resin (B) is composed of resin waste generated in the molding of the thermosetting polyurethane-based resin.   (1) The polyurethane resin (A) is a reaction product of at least one aromatic diisocyanate selected from arene diisocyanates and diphenylalkane diisocyanates and a polyether polyol, (2) polyurethane resin (B) is a pulverized product of resin waste produced in cast molding of a thermosetting polyurethane resin, and is a powdery polyurethane resin having an average particle size of 500 μm or less. (3) Polyurethane resin (B 2) The resin composition according to claim 1, wherein the ratio of 1) to 25 parts by weight with respect to 100 parts by weight of the polyurethane resin (A).   The resin composition according to claim 1, further comprising at least one curing agent selected from amine-based curing agents and alcohol-based curing agents.   A molded article formed from the resin composition according to claim 1.   The molded article according to claim 8, which is a cast molded article.   A method for producing a cast-molded product by cast-molding the resin composition according to claim 1.