JPS59145213A - Production of polyurethane elastomer of low dynamic heat build-up - Google Patents

Abstract

PURPOSE:To produce the titled elastomer having low heat build-up and excellent solvent resistance, by conducting the reaction of a specified urethane prepolymer with a specified polyol one or both of which contain an epsilon-caprolactone chain. CONSTITUTION:An isocyanato group-terminated urethane prepolymer obtained by reacting W1pts.wt. polyol containing 0-95wt% epsilon-caprolactone chain and having a molecular weight MW1>=500 and an (average)hydroxyl group functionality F1>=2 (polyol A) with W2pts.wt. organic polyisocyanate having an (average) isocyanate group functionality F2>=2 is reacted with W3pts.wt. polyol containing 0-95wt% epsilon-caprolactone chain and having a molecular weight MW2<=5,000 and an (average) hydroxyl group functionality F3>=2.2 (polyol B) to obtain the titled elastomer which is a polyurethane elastomer having a crosslinking density (CD) >=0.085 (determined from the equation, wherein MW2 is the MW of an organic polyisocyanate) and in which one or both of polyols A and B contain an epsilon-caprolactone chain.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyurethane elastomer with little dynamic heat generation.

Polyurethane elastomers are used in various applications such as architecture, vehicles, aircraft mechanical parts, and road paving due to their excellent physical properties, but they are especially used in mechanical parts such as printing or paper rolls, rollers, and anti-vibration rubber. Polyurethane elastomers are used as rubber materials in tires, etc., taking advantage of their properties such as wide range of hardness, high elasticity, and high strength.

The polyurethane Ex-1 hemer used for this purpose is
Polyurethane elastomers made from polyester polyols, polyether polyols, etc. are commonly used.

The locations where polyurethane elastomer is used as the rubber material for the mechanical parts generally tend to generate heat due to repeated loads.

As a result of fever, (1) The inside of the polyurethane elastomer melts.

(2) The polyurethane ex-1-mer expands and changes in size.

(3) The temperature of the polyurethane ex-1-mer increases, the mechanical strength changes, and at the same time, oxidative deterioration is likely to occur.

Such disadvantages arise.

The present inventors have completed the present invention as a result of intensive research in view of the conventional drawbacks as described above. That is, (a) a polyol (hereinafter referred to as a polyol (I )) and 2 parts by weight of an organic polyisocyanate-1-W having an incyane-1-group number or an average isocyanate-1-group number F2 of 2 or more; (b) A polyol containing 0.-95% by weight of ε-caprolactone chains in the molecule, a molecular weight (3) of 5000 or less, and a hydroxyl group number or average hydroxyl group number F3 of 2.2 or more (hereinafter referred to as 1). )) is a polyurethane elastomer obtained by reacting 3 parts by weight of IA, wherein the combination of polyol (a) and polyol (b) is such that one or both of them have E-
A method for producing a polyurethane elastomer with low dynamic heat generation, which contains a cabrolane 1-one chain and has a polyurethane ex-mer crosslinking density CI) of 0.085 or more as determined by the following formula: It is.

S1 cut F+ -2) :MJ +I+h X(F2-2
): HIj2+l113 X (F3-2): MJC
I) = S1 + W2 + W3 100O [Ml112 is the molecular weight of organic polyisocyanate-1-. ] As the polyol (a), polyether boryl such as polytetra-1-ramethylene glycol, polyoxyethylene polyol, polyoxypropylene polyol, polyoxyethylene oxypropylene polyol, polyethylene adipe 1-, polybutylene adipe 1- , polyhexamethylene adipe-1~, polyester polyols such as castor oil, polyolefin polyols such as polybutadiene polyol, or mixtures of the above polyols, or 95 ε-caprolactone chains in the molecule of the above polyols.
A polyol in which E-caprolavone is added to the above polyol, or a mixture with the above polyol, such that the molecular weight MWI is 500 or more, and the number of hydroxyl groups or the average number of hydroxyl groups FN is 2. Above, preferably 2 or more and 4 or less.

Among them, the number of hydroxyl groups or the average number of hydroxyl groups 1? '' is 3
In this case, it is preferable that the molecule contains 0 to 95% by weight of ε-caprolacone chains and has a molecular weight MJ of 2500 or more. Isocyanate 1-base or average isocyanate 1-
Examples of the organic polyincyane 1- having a base number F2 of 2 or more (hereinafter referred to as organic polyisocyane 1-) include tolylene diisocyane h (TI) I), diphenylmethane diisocyane-1- (MIH), and 1.5 naphthalene diisocyanate. (NDI), xylylene diisocyanate 1~(
XDI), hexamethylene diisocyanate (IIDI), hydrogenated TDI, hydrogenated TDI (H
12M January), hydrogenated XDi, isophorone diisocyanate, a modified product thereof, or a mixture thereof, and the number of groups to isocyane 1 or the average number of isocyane 1 to groups F2 is 2 or more, preferably 2 or more,
3 or less can be listed.

The polyol (b) includes (1) 95% by weight of E-caprolactone chains in the molecules of polyether polyols such as polyoxyethylene polyol, polyoxypropylene polyol, and polyoxyethylene oxypropylene polyol, and polynisterol such as castor oil. A polyol obtained by adding E-caprolactone to the above-mentioned polyol, or a mixture with the above-mentioned polyol, etc., having a molecular weight M of 5,000 or less and a number of hydroxyl groups or an average number of hydroxyl groups of 2.2 or more as shown below. , (2) Polyols such as trimethylolpropane, glycerin, pentaerythryl-(3) (
A) Polyether polyols such as polyoxyethylene polyol, polyoxypropylene polyol, polyoxyethylene oxypropylene polyol, polyester polyols such as castor oil, polyolefin polyols such as polybutane diene polyol, or a mixture of the above polyols, or a mixture of the above polyols. A polyol obtained by adding ε to prolactone to the above polyol, the polyol of (2) above, or a mixture thereof, such that the E-caprolactone chain is 95% by weight or less in the molecule. and CB) polyether polyols such as polytetramethylene glycol, polyoxyethylene polyol, polyoxypropylene polyol, polyoxyethylene oxypropylene polyol, polyethylene adipate, polyol, etc. Polystyl polyols such as butylene adipate, polyolefin polyols such as polybutadiene polyol, polyols such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, or ε-force brolactone in the molecule of the polyol.
A polyol in which ε-caprolactone is added to the above polyol so that the chain content is 95% by weight or less, or a mixture thereof, and the number of hydroxyl groups or the average number of hydroxyl groups is 2.
A mixed polyol containing less than 2 polyols, containing 0 to 95% by weight of ε-cabrolacone chains in one molecule.
Examples include mixed polyols having a molecular weight MW of 5,000 or less and an average number of hydroxyl groups of 2.2 or more. Among them, the molecular weight Mu3 of polyol (b) is 30
00 or less is preferable.

In polyol (a) and polyol (b),
When adding E-caprolactone to various polyols,
According to a known method, using an organometallic compound such as an organotitanium compound or an organotin compound as a catalyst, the temperature is 110 to 1.
Perform at 60°C.

Examples of ε-caprolactone include those commonly used.

Next, as a combination of polyol (a) and polyol (b), one or both of them may contain an ε-caprolactone chain in the molecule.

If one or both of polyol (a) and polyol (b) does not contain a predetermined amount of E-caprolactone in the molecule, the object of the present invention will not be achieved.

In polyol (a), organic polyisocyanate 1- and polyol (b), when mixed polyol (a), mixed organic polyisocyanate and mixture polyol (b) consisting of two or more types are used, the molecular weight, average number of hydroxyl groups, Alternatively, the average number of isocyanate groups is determined as follows.

- Polyol (a) will be described as an example.

Type of polyol (a) Part by weight Number of hydroxyl groups Molecular weight Polyol (1) Lit (1),
F * (1) In the case of a mixture of two types of decoy 1 (1); S t (L) + w 1 (2) 'J t (1) / MV 1 - (1) + W t (2)
/Mlil t (2)W t (1)/MW t <
1) + W t <2)/MW 1 (2) Polyol (a), organic polyisocyanate and polyol (
The blending amounts of b), ie, 111 parts by weight, 1112 parts by weight, and 3 parts by weight, are such that the crosslinking density CD of the polyurethane determined by the above formula is 0.085 or more.

In the case of each compounding amount such that the crosslink density CD is less than 0.085, the object of the present invention cannot be achieved. 'Next, the urethane prepolymer containing terminal isocyanate groups of the present invention (hereinafter referred to as urethane prepolymer)
It is obtained by uniformly mixing 1 part by weight of v1 and 2 parts by weight of organic polyisocyanate and reacting the mixture at 40 to 150°C for 10 minutes to 10 hours.

In this case, when the isodex ep determined by the following formula is small, the obtained urethane prepolymer has a high viscosity and may gel. Furthermore, when Ip exceeds 2, free isocyanate monomer is present in the urethane prepolymer, which is unfavorable from the viewpoint of the working environment.

Therefore, Ip is preferably 1.1 or more and 2.0 or less, but is not particularly limited.

Number of NGO groups W2/MW2Xp2 I p = -=:-11--- 〇Number of H groups wt/MWIXF1 Next, the polyurethane elastomer is made by combining parts by weight of the urethane prepolymer (Wx+V2) obtained above and polyol. (b) 3 parts by weight, and further a catalyst, a plasticizer, if necessary,
Additives such as antifoaming agents and colorants are added, mixed uniformly, and reacted.

In this case, the ratio of 011/NCO between the urethane prepolymer and the polyol (b) is preferably 0.5 to 1.3.

Further, in order to advance the reaction, that is, to accelerate curing, it is preferably heated to a temperature of 80 to 140°C.

If the temperature is low, curing will be delayed, and if the temperature is high, side reactions may occur during curing or deterioration of the polyurethane elastomer. The polyurethane ex-l-mer obtained has a crosslinking density CD of 0.085 or more as determined by the above formula, preferably 0.09 to 0.35. When the crosslinking density CD is less than 0.085, the polyurethane elastomer generates a large amount of heat under repeated loads. Also 0,35
If it exceeds this, brittleness may appear in the polyurethane elastomer.

Although it is not certain that the polyurethane elastomer of the present invention generates less heat under repeated loading, it is thought to be as follows.

Polyurethane elastomers generally consist of hydrogen bond crosslinking and chemical crosslinking. Crosslinking by hydrogen bonds is
Chemical crosslinks do not dissociate, although they tend to dissociate at high temperatures. When heat is generated due to repeated loading, the crosslinks due to hydrogen bonds are dissociated, so the amount of deformation increases and the heat generation also increases. Chemical crosslinks do not dissociate even when the temperature rises, so they are less susceptible to such adverse effects.

Furthermore, the ester group tends to form a water-water bond with the hydrogen of the urethane group, which increases heat generation, but on the other hand, improves solvent resistance.
When a moderate amount of ester groups are present in the same molecule, a suitable balance between solvent resistance and heat generation is achieved.

The polyurethane elastomer of the present invention has a chemical crosslinking, that is, a crosslinking density CD of 0.085 or more, generates little heat, and has an appropriate amount of ester groups, so it also has excellent solvent resistance.

The polyurethane elastomer of the present invention generates very little heat when subjected to repeated loads. In other words, because there is little dynamic heat generation, there is no thermal expansion of the polyurethane elastomer, which not only provides stable dimensions when made into mechanical parts, but also reduces deterioration of the elastomer due to heat generation, resulting in long parts life and reliability. It gets expensive.

Furthermore, when used in various rolls, the rotational speed can be increased, which improves productivity while also providing excellent stickiness and solvent resistance.

Therefore, it is ideal as a rubber material for mechanical parts, such as various rolls, rollers, especially printing rolls, etc.

Examples of the present invention will now be described in detail.

Production Example-I Polyoxypropylene glycol (molecular weight 1000) 5
00 parts by weight and 0.2 parts by weight of dibutyltin dilaurate were placed in an IQ flask and heated to 140°C. E
-Caprolav 1-2500 parts by weight is added dropwise over 1 hour, and then reacted at 140 to 150°C for 5 hours. After the reaction, a white wax-like polyol was obtained in the chamber.

The hydroxyl value of this polyol is 56.9mgKOH/g
' (molecular weight 2000), and the ε-caprolacone chain accounted for 50%.

Production Example 2 The same procedure as Production Example 1 was carried out except that 500 parts by weight of polyoxypropylene glycol (molecular weight 1000) in Production Example -1 was replaced with 500 parts by weight of polyoxypropylene triol (molecular weight 1500).

The hydroxyl value of the obtained polyol was 56, 2mgKO1
l/g (molecular weight 3000), and ε-cabrolac 1-
The chain content was 50% by weight.

Production Example 3 The same procedure as Production Example 1 was carried out except that 500 parts by weight of polyoxypropylene glycol (molecular weight 1000) in Production Example 1 was replaced with 500 parts by weight of polytetramethylene glycol (molecular weight 1000).

The hydroxyl value of the obtained polyol was 54, 6 mg KOI
I/g (molecular weight 2000), and the E-force prolactone chain was 50% by weight.

Example-1 (1) Method for producing polyurethane elastomer Polyol (
b) A urethane prepolymer was obtained by reacting parts by weight of Wt and 2 parts by weight of organic polyisocyanate at 80 to 100°C until a predetermined free isocyanate concentration was reached.

Parts by weight of this urethane prepolymer (v1+W2) and parts by weight of polyol (b) Wa are defoamed and mixed with 4 parts by weight of a non-reactive plasticizer, and the mixture is poured into a mold coated with a release agent in advance at 130°C for 3 hours. hardened.

After curing, a polyurethane elastomer was obtained. (2) Tests on heat generation and physical properties of polyurethane elastomer Heat generation (calorific value) and physical properties (hardness, tensile strength, and elongation) tests were conducted on the polyurethane elastomer obtained above.

In addition, the heat generation test is based on A of A S 1' M IJ 623.
The method (Gutu 1-Rich Flexometer) and physical property tests were conducted in accordance with JIS K6301. The results are shown in Table 1.

Application example: On a core with a diameter of 10 Cnl and a length of 30 cm, a thickness of 5
Two rolls coated with polyurethane elastomer of Example Experimental Nal were made so that the thickness was 0 cm. When the two rolls were tightened with a force of 400 kg, the contact width between the two rolls was 2.511111.

In this state, the roll was rotated at 150 rpm for 3 hours. The contact width between the rolls was 2.8+nm, and the temperature rise on the roll surface was 7°C.

Similarly, the polyurethane elastomer of Comparative Example-2 was used.

The contact width of the rolls changed from 2.4mm to 4.8+n+n.

The temperature rise on the roll surface was 32°C.

As mentioned above, the polyurethane elastomer of the present invention was found to have little dynamic heat generation and excellent physical properties.

patent applicant Daiichi Kogyo Seiyaku Co., Ltd.

Claims (1)

[Scope of Claims] (a) 0 to 95% by weight of [-caprolactone chains in the molecule]
A polyol (
The weight part of Vt (hereinafter referred to as polyol (a)) and the number of groups F2 from 1 to isothiaphor or the average number of groups F2 from 1 to 2
A urethane prepolymer containing terminal isocyanate groups obtained by reacting 12 parts by weight of the above organic polyisocyanate, and (b) 0 to 95% by weight of E-caprolactone chains in the molecule.
containing a polyol (
A polyurethane elastomer obtained by reacting 3 parts by weight of polyol (hereinafter referred to as polyol (q)), wherein the combination of polyol (a) and polyol (b) is such that one or both of them have ε- A polyurethane elastomer containing a caprolactone chain has a crosslinking density CD of 0.
Production method of polyurethane elastomer with low dynamic heat generation characterized by having a molecular weight of 085 or more wlX (F 1-2): MW s +W2X (F2-
2): MW2+Ws