JP2010150475A - Polyurethane resin composition and polyurethane resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyurethane resin having low viscosity enabling sufficient mixing, showing small change in hardness under high temperature conditions after hardened, causing no melting of the resin, thereby sufficiently adhering to a substrate over a long time and maintaining heat radiating property and heat resistance over a long time. <P>SOLUTION: The polyurethane resin composition includes (A) a hydroxy group-containing conjugated diene polymer, (B) at least one hydrogenated polyol selected from a hydrogenated hydroxy group-containing conjugated diene polymer and a hydrogenated castor oil-based polyol, (C) a polyisocyanate, (D) an inorganic filler, (E) a phosphoric ester, and (F) a plasticizer. The composition is hardened to give a polyurethane resin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyurethane resin composition and a polyurethane resin. More specifically, since the change in hardness under high-temperature conditions is small and the resin does not melt after curing, the resin sufficiently adheres to the substrate for a long period of time. The present invention relates to a polyurethane resin composition capable of maintaining heat dissipation and heat resistance over a long period of time, and a polyurethane resin obtained by curing the polyurethane resin composition.

  Conventionally, in an electronic circuit board used for electrical appliances, etc., in order to protect electronic components from moisture etc., a sealing material made of a flame-retardant heat-release polyurethane resin composition having a high volume resistance is used. The entire substrate is sealed (Patent Document 1). However, many electronic components that generate heat during operation are attached to the electronic circuit board. In recent years, electronic circuits have been integrated and highly functionalized as seen in LSIs, etc. At the same time, the heat generation is becoming local. Thus, in order to efficiently remove the heat generated from the electronic component, it is necessary that the sealing material is in close contact with the circuit board or the electronic component for a long period of time, so that the change in hardness under high temperature conditions is small. is necessary. Moreover, since the heat dissipation polyurethane resin used as a sealing agent is used in a state of being in close contact with an electronic component as described above, it is also necessary to maintain heat dissipation and heat resistance over a long period of time.

In view of these points, various heat-dissipating polyurethane resin compositions have been developed (Patent Documents 2 to 7), but none of the conventional problems have been found. Here, as the polyol component, for example, a hydroxyl group-containing conjugated diene polymer such as polyptadiene polyol may be blended. In this case, however, the resin hardness does not increase when used for a long time under high temperature conditions. There is a tendency that it cannot be sufficiently adhered to the substrate over a long period of time, and there is a problem that high heat dissipation cannot be maintained over a long period of time. In addition, it is conceivable to use a hydrogenated product of a hydroxyl group-containing conjugated diene polymer or a hydrogenated product of castor oil-based polyol as the polyol, but in this case, the polyurethane resin tends to soften when used for a long time under high temperature conditions. In particular, when the hardness of the resin is lowered in order to improve the adhesion to the substrate, there is a problem that the polyurethane resin is likely to melt at a high temperature. Therefore, a heat-dissipating polyurethane resin composition that is satisfactory in all performances has not been obtained. Especially, since the change in hardness under high temperature conditions is small and the resin does not melt, it is sufficient for a substrate for a long period of time. The actual situation is that a polyurethane resin that adheres and can maintain heat dissipation and heat resistance over a long period of time has not been obtained.
JP 2000-226426 A JP 2002-121529 A JP 2002-134666 A JP 2003-133493 A JP 2003-138130 A JP 2004-300300 A JP 2007-131830 A

  The present invention has been made in view of the above prior art, and the object of the present invention is that, after curing, the change in hardness under high temperature conditions is small and the resin does not melt. It is providing the polyurethane resin composition which can fully adhere | attach, and can maintain heat dissipation and heat resistance over a long period of time, and the polyurethane resin which hardened this.

  The polyurethane resin composition of the present invention comprises (A) a hydroxyl group-containing conjugated diene polymer, (B) a hydrogenated product of a hydroxyl group-containing conjugated diene polymer, and a hydrogenated product of castor oil-based polyol. It contains an added polyol, (C) polyisocyanate, (D) an inorganic filler, (E) a phosphate ester represented by the general formula (1), and (F) a plasticizer. And

  In the polyurethane resin composition of the present invention, the polyol component is at least selected from (A) a hydroxyl group-containing conjugated diene polymer, (B) a hydrogenated product of a hydroxyl group-containing conjugated diene polymer, and a hydrogenated product of castor oil-based polyol. Since one kind of hydrogenated polyol is blended, after curing, the problem of resin hardness increase under high temperature conditions, which is a concern due to blending of the (A) hydroxyl group-containing conjugated diene polymer, is solved, B) The problem of melting of the polyurethane resin, which is a concern due to the blending of the hydrogenated polyol, is solved, and heat dissipation and heat resistance can be maintained over a long period of time.

  Moreover, in the polyurethane resin composition of the present invention, since (E) phosphate ester represented by the general formula (1) is blended, even when (D) the inorganic filler is used at a high blending ratio, The polyurethane composition can be uniformly mixed while maintaining a relatively low viscosity.

  The polyurethane resin of the present invention is obtained by curing the polyurethane resin composition.

  The polyurethane resin composition of the present invention is at least one selected from (A) a hydroxyl group-containing conjugated diene polymer, (B) a hydrogenated product of a hydroxyl group-containing conjugated diene polymer and a hydrogenated product of castor oil-based polyol as a polyol component. Since it contains a seeded hydrogenated polyol, the change in hardness under high-temperature conditions is small after curing and the resin does not melt, so that it can sufficiently adhere to the substrate over a long period of time. Therefore, heat dissipation and heat resistance are maintained over a long period of time.

  The polyurethane resin composition of the present invention comprises (A) a hydroxyl group-containing conjugated diene polymer and (B) a hydrogenated product of a hydroxyl group-containing conjugated diene polymer and a hydrogenated product of castor oil-based polyol. A polyurethane resin is produced by a reaction between the polyol and (C) polyisocyanate.

  Examples of the hydroxyl group-containing conjugated diene polymer (A) used in the polyurethane resin composition of the present invention include polyptadiene polyol and polyisoprene polyol.

  In addition, examples of the hydrogenated product of the hydroxyl group-containing conjugated diene polymer (B) that is one of the hydrogenated polyols include those obtained by adding hydrogen to the compound exemplified as the above (A) hydroxyl group-containing conjugated diene polymer. . The iodine value of the hydrogenated product of the hydroxyl group-containing conjugated diene polymer is preferably 20 g / 100 g or less, and more preferably 10 g / 100 g or less. If the iodine value is larger than the above range, the increase in hardness under high temperature conditions becomes large, and it may not be possible to sufficiently adhere to the substrate.

  Further, hydrogenated castor oil-based polyol (B), a hydrogenated polyol, includes hydrogenated castor oil hydrogenated to castor oil, hydrogenated castor oil fatty acid and hydrogenated castor oil obtained by adding hydrogen to castor oil fatty acid. Examples thereof include hydrogenated castor oil-modified polyol obtained by use. In the following description, “hydrogenation” means “hydrogenated product”.

  Examples of the hydrogenated castor oil-modified polyol include transesterification products of hydrogenated castor oil and fats other than hydrogenated castor oil, esterification products of hydrogenated castor oil and hydrogenated fat fatty acids including hydrogenated castor oil fatty acids, hydrogenated Esterification reaction product of castor oil and polyhydric alcohol, reaction product of hydrogenation castor oil fatty acid and polyhydric alcohol, esterification of a part of hydroxyl groups contained in hydrogenated castor oil with monocarboxylic acid such as acetic acid Such as things.

  (B) The iodine value of the hydrogenated product of castor oil-based polyol is preferably 20 g / 100 g or less, more preferably 10 g / 100 g or less. If the iodine value is larger than the above range, the increase in hardness under high temperature conditions becomes large, and it may not be possible to sufficiently adhere to the substrate.

  In the polyurethane resin composition of the present invention, the blending weight ratio of (A) hydroxyl group-containing conjugated diene polymer and (B) hydrogenated polyol is preferably in the range of 1/99 to 90/10. More preferably, the ratio is in the range of / 95 to 50/50. (A) When there are many compounding ratios of a hydroxyl-containing conjugated diene polymer, the tendency for the hardness rise of resin under high temperature conditions to become large appears. Moreover, when there are many compounding ratios of (B) hydrogenated polyol, the tendency for the hardness of polyurethane resin to fall significantly and to melt | dissolve will appear at high temperature.

  Examples of the (C) polyisocyanate that can be used in the polyurethane resin composition of the present invention include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and araliphatic polyisocyanates.

  Aliphatic polyisocyanates include tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1 , 5-diisocyanate, 3-methylpentane-1,5-diisocyanate and the like.

  Examples of the alicyclic polyisocyanate include isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, and the like. Can be mentioned.

  Aromatic polyisocyanates include tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), polymethylene polyphenyl polyisocyanate, 4,4′- Examples thereof include dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and the like.

  Examples of the araliphatic polyisocyanate include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α, α, α, α-tetramethylxylylene diisocyanate, and the like.

  Moreover, modified bodies, such as a carbodiimide body, an allophanate body, a burette body, an isocyanurate body, an adduct body, etc. of these organic polyisocyanates can be mentioned. In addition, these can also be used individually or in combination of 2 or more types.

  Of these, aliphatic polyisocyanates and alicyclic polyisocyanates are preferable from the viewpoint that discoloration hardly occurs, and hexamethylene diisocyanate-modified isocyanurate, hexamethylene diisocyanate-modified burette, and hexamethylene diisocyanate-modified adduct. Is more preferable.

  Moreover, in this invention, you may use the urethane prepolymer obtained by making the said polyisocyanate and (B) polyol which has a specific structure react on isocyanate group excess conditions as (C) polyisocyanate.

  In the polyurethane resin composition of the present invention, the molar ratio of the isocyanate group contained in the (C) polyisocyanate component and the sum of the hydroxyl group contained in the (A) hydroxyl group-containing conjugated diene polymer and (B) hydrogenated polyol ( NCO / OH) is preferably 0.3 to 1.1. If the molar ratio of isocyanate groups to hydroxyl groups is less than this range, the resulting resin will have low heat resistance, and if it is greater than this range, the resin will be hard and may not be able to sufficiently adhere to the substrate. is there.

  Examples of the inorganic filler (D) blended in the polyurethane resin composition of the present invention include metal oxides such as alumina, metal nitrides such as aluminum nitride and boron nitride, and metals such as aluminum hydroxide and magnesium hydroxide. A hydroxide etc. can be mentioned.

  (D) The inorganic filler is preferably at least two types of mixtures having different average particle diameters. Specifically, the ratio (DL) / (DS) of the average particle diameter of the inorganic filler having the largest (DL) average particle diameter and the inorganic filler having the smallest (DS) average particle diameter is 1.5 to 100 is preferable, and 2 to 50 is more preferable. By making it within the above range, the viscosity of the polyol component can be further reduced.

  Further, the weight ratio of the inorganic filler having the largest (DL) average particle diameter and the inorganic filler having the smallest (DS) average particle diameter is (DL) / (DS) = 99/1 to 50/50. Is preferred.

  (D) The amount of the inorganic filler is preferably 30 to 95% by weight, more preferably 50 to 95% by weight, and more preferably 60 to 95, when the polyurethane resin composition is 100% by weight. More preferably, it is 70% by weight, most preferably 70% by weight. (D) When the amount of the inorganic filler is greater than the above range, the initial mixed viscosity tends to be too high, and when it is less than the above range, sufficient heat dissipation tends to be difficult to obtain.

  Furthermore, (E) phosphoric acid ester represented by General formula (1) is mix | blended with the polyurethane resin composition of this invention.

Here, R is a hydrocarbon group having 1 to 30 carbon atoms, m is an integer of 0 to 20, n is an integer of 1 to 20, and R ′ is OH or a group represented by the general formula (2). In 1) and general formula (2), R ″ is CH ₃ or CH ₂ CH ₃ , and “/” represents that the oxyalkylene groups described on the left and right sides thereof may be block addition or random addition.

  This (E) phosphate ester can be obtained, for example, by reacting a polyether monool obtained by adding an alkylene oxide to a monoalcohol having 1 to 30 carbon atoms by a known method and anhydrous phosphoric acid. In addition, the said alkylene oxide should just have ethylene oxide as an essential component, and can also use propylene oxide and butylene oxide together. Furthermore, the number of added moles of alkylene oxide and the reaction ratio between the polyether monool and phosphoric anhydride are appropriately selected so as to satisfy the condition of the general formula (1).

  The compounding quantity of (E) phosphate ester represented by General formula (1) used for the polyurethane resin composition of this invention is 0.01-2 weight when a polyurethane resin composition is 100 weight%. % Is preferable, and a range of 0.01 to 1% by weight is more preferable. When the above range is exceeded, it is difficult to obtain a further viscosity-reducing effect due to an increase in the amount used, and the physical properties of the polyurethane resin also tend to be reduced, and below the above range, the addition of (E) phosphate ester The effect of reducing viscosity cannot be obtained.

  Furthermore, (F) plasticizer is mix | blended with the polyurethane resin composition of this invention. Plasticizers include phthalic acid diesters such as dioctyl phthalate, diisononyl phthalate and diundecyl phthalate, adipic acid diesters such as dioctyl adipate and diisononyl adipate, methyl acetyl ricinoleate, butyl acetyl ricinoleate, acetylated ricinoleic acid triglyceride, acetylated poly Castor oil esters such as ricinoleic acid triglyceride, phosphate triesters such as tricresyl phosphate and trixylenyl phosphate, trimellitic esters such as trioctyl trimellitate and triisononyl trimellitate, tetraoctyl pyromellitate, etc. And pyromellitic acid esters.

  The blending amount of the plasticizer (F) is preferably 1 to 30% by weight, more preferably 3 to 20% by weight, and more preferably 5 to 15 when the polyurethane resin composition is 100% by weight. More preferred is weight percent. When the blending amount of the plasticizer is less than the above range, it is difficult to obtain a sufficient viscosity reducing effect of the polyol component and the flexibility of the polyurethane resin. Various physical properties such as

  Various additives such as an antioxidant, a hygroscopic agent, an antifungal agent, and a silane coupling agent can be added to the polyurethane resin composition of the present invention as necessary. For example, as an antioxidant, phenol-containing antioxidants such as dibutylhydroxytoluene (BHT), tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate] methane, Phosphorus-containing antioxidants such as phenyl diisodecyl phosphite, sulfur-containing antioxidants such as dilauryl-3,3′-thiodipropionic acid ester, 2,4-bis (n-octylthio) -6- (4-hydroxy- An antioxidant containing phenol and sulfur in one molecule such as 3 ′, 5′-di-t-butylanilino) -1,3,5-triazine can be mentioned. When using antioxidant, when a polyurethane resin composition is 100 weight%, it is preferable to add in 0.01-5 weight%. Further, examples of the hygroscopic agent include zeolite, hydraulic alumina, calcium chloride and the like. When using a hygroscopic agent, it is preferable to add in the range of 0.1 to 3% by weight when the polyurethane resin is 100% by weight.

  In preparing the polyurethane resin composition of the present invention, a catalyst may be added in order to accelerate the curing of the polyurethane resin. As the catalyst, a metal catalyst or an amine-based catalyst usually used for producing a polyurethane resin can be used. Metal catalysts include tin catalysts such as dibutyltin dilaurate, dioctyltin dilaurate and dibutyltin dioctate, lead catalysts such as lead octylate, lead octenoate and lead naphthenate, bismuth catalysts such as bismuth octylate and bismuth neodecanoate, etc. Can be mentioned. Examples of the amine catalyst include diethylenetriamine.

  The polyurethane resin composition of the present invention preferably has a hardness according to type A after curing of 80 or less, and more preferably 50 or less. Furthermore, it is preferable that the heat conductivity after hardening is 1 W / m · K or more.

  Hereinafter, based on an Example and a comparative example, the polyurethane resin composition and polyurethane resin of this invention are demonstrated in detail. In the present specification, “parts” and “%” represent “parts by weight” and “% by weight”, respectively, unless otherwise specified.

  Table 1 shows raw materials (excluding the component (E)) used in the following Examples and Comparative Examples. (E) The phosphoric acid ester component was synthesized as follows.

(E-1: Synthesis of phosphate ester 1)
Using lauryl alcohol as a starting material, 2 mol of propylene oxide and 8 mol of ethylene oxide were block-added by a known method to obtain an alkylene oxide adduct of lauryl alcohol.

  Subsequently, 300 g of the above alkylene oxide adduct of lauryl alcohol and 27.1 g of phosphoric anhydride were charged in a four-necked flask at a molar ratio of 2.4: 1 and reacted at 70 ° C. for 4 hours with stirring. To obtain phosphoric acid ester 1 (theoretical substitution number 1.2 of OH group of phosphoric acid).

(E-2: Synthesis of phosphate ester 2)
Tridecyl alcohol was used as a starting material, and 10 mol of ethylene oxide was added using a known method to obtain an alkylene oxide adduct A of tridecyl alcohol.

  Subsequently, 300 g of the above tridecyl alcohol alkylene oxide adduct A and 22.2 g of phosphoric anhydride were charged in a four-necked flask at a molar ratio of 3: 1 and stirred at 70 ° C. for 4 hours. Reaction was carried out to obtain phosphoric acid ester 2 (theoretical substitution number 1.5 of OH group of phosphoric acid).

(E-3: Synthesis of phosphate ester 3)
Tridecyl alcohol was used as a starting material, and 7 mol of ethylene oxide was added using a known method to obtain an alkylene oxide adduct B of tridecyl alcohol.

  Subsequently, 300 g of the above-mentioned alkylene oxide adduct B of tridecyl alcohol and 23.3 g of phosphoric anhydride were charged in a four-necked flask at a molar ratio of 3.6: 1 at 70 ° C. with stirring. Reaction was performed for 4 hours to obtain phosphoric ester 3 (theoretical substitution number of phosphoric acid OH group 1.8).

(Production of polyurethane resin composition)
The polyurethane resin compositions of Examples 1 to 7 and Comparative Examples 1 to 5 were prepared according to the formulation shown in Table 2. In the preparation, among the components shown in Table 2, (C) the component other than the polyisocyanate component was mixed for 3 minutes at 2000 rpm using a mixer (trade name: Awatori Nertaro, manufactured by Shinky Corp.), then 25 Adjusted to ° C. Then, the polyisocyanate component adjusted to 25 degreeC was added to this mixture, and the polyurethane resin composition of each Example and each comparative example was obtained by mixing for 1 minute at 2000 rpm using the mixer same as the above.

(Manufacture of polyurethane resin)
Next, a polyurethane resin test piece was prepared using the polyurethane resin composition prepared above. First, the polyurethane resin composition was filled in a 110 × 110 × 10 mm mold, covered and cured at 23 ° C. for 48 hours, and then demolded to obtain a polyurethane resin test piece.

<Performance test>
For the compositions and resins of Examples 1 to 7 and Comparative Examples 1 to 5 obtained above, the viscosity, thermal conductivity, hardness (type A and type C) at the initial mixing stage, and after the heat resistance test The hardness (type A and type C) was evaluated. The test results are also shown in Table 2. Each test method is as follows.

(Initial mixing viscosity)
The obtained polyurethane resin composition was adjusted to 25 ° C., and the viscosity 10 minutes after the start of mixing was measured using a BH viscometer.

(Thermal conductivity)
The thermal conductivity was measured according to JIS R2618 using a thermal conductivity meter (manufactured by Kyoto Electronics Industry Co., Ltd., QTM-D3).

(Hardness (Type A and Type C))
It measured according to JIS K6253.

(Hardness after heat resistance test (Type A and Type C))
Hardness (type A and type C) was measured according to JIS K6253 for a test piece of polyurethane resin that was allowed to stand for 200 hours under the condition of 150 ° C.

<Test results>
The polyurethane resin compositions of Examples 1 to 7 all had a mixable viscosity. On the other hand, the polyurethane resin compositions of Comparative Examples 1 to 5 containing no phosphate ester were higher in viscosity than Examples 1 to 7. Moreover, it turns out that the polyurethane resin composition of Examples 1-7 has a small hardness change after a heat resistance test, and is excellent in heat resistance. On the other hand, the polyurethane resins of Comparative Examples 1 and 2 showed a significant increase in hardness, and Comparative Examples 3 to 5 showed a significant decrease in hardness.

  The polyurethane resin composition of the present invention has a small change in hardness under high-temperature conditions after curing and does not cause melting of the resin. Therefore, the polyurethane resin composition sufficiently adheres to the substrate over a long period of time, and has a long period of heat dissipation and heat resistance. Therefore, it can be used in fields such as electrical products and electronic parts.

Claims (5)

(A) a hydroxyl group-containing conjugated diene polymer;
(B) at least one hydrogenated polyol selected from a hydrogenated hydroxyl group-containing conjugated diene polymer and a hydrogenated castor oil-based polyol;
(C) a polyisocyanate;
(D) an inorganic filler;
(E) a phosphate ester represented by the general formula (1);
(F) A polyurethane resin composition containing a plasticizer.

(R is a hydrocarbon group having 1 to 30 carbon atoms, m is an integer of 0 to 20, n is an integer of 1 to 20, R ′ is OH or a group represented by the general formula (2), and the general formula (1) In the general formula (2), R ″ is CH ₃ or CH ₂ CH ₃ , and “/” represents that the oxyalkylene groups described on the left and right thereof may be block addition or random addition.

  2. The polyurethane resin composition according to claim 1, wherein the polyurethane resin composition contains 30 to 95 wt% of the (D) inorganic filler when the polyurethane resin composition is 100 wt%.   The polyurethane according to claim 1 or 2, wherein the weight ratio of the (A) hydroxyl group-containing conjugated diene polymer and the (B) hydrogenated polyol is in the range of 1/99 to 90/10. Resin composition.   4. The composition according to claim 1, wherein the polyurethane resin composition contains 0.01 to 2% by weight of a phosphoric acid ester represented by the general formula (1) when the polyurethane resin composition is 100% by weight. Polyurethane resin composition.   A polyurethane resin obtained by curing the polyurethane resin composition according to claim 1.