JPS61276814A - Polyurethane elastomer - Google Patents

Abstract

PURPOSE:To provide the titled polymer composed of a specific polyester triol having low melting point or its mixture with a specific polyester having low melting point, having excellent flexibility and elastic recovery and producible in high workability. CONSTITUTION:The objective polymer having a hardness of 10-50 deg. can be produced by mixing (A) 0-90mol% polyester polyol resin composed of polyhydric alcohol containing 30-100(wt)% 3-10C dihydric alcohol having side chain, a polybasic acid and 30-80% epsilon-caprolactone, and having a melting point of <=30 deg.C and a molecular weight of 1,000-10,000 and (B) 100-10mol% polyester polyol resin composed of polyhydric alcohol containing 30-100% 3-10C trihydric alcohol having side chain, a polybasic acid and 30-80% epsilon- caprolactone and reacting the mixture with a polyisocyanate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polyurethane elastomer, and particularly to a polyurethane elastomer that is flexible and has improved workability during production.

Polyurethane nystomer has superior mechanical strength and abrasion resistance compared to rubber, and has good weather resistance and chemical resistance and can withstand long-term use, so it has been used as a material for conventional mechanical parts and chemical equipment. In addition to industrial applications, it has also been widely used in solid tires, vibration-proofing materials, shock-absorbing materials, printing rolls, etc. In particular, it has recently begun to be used in a wide variety of fields, such as as a soft roll material for OA equipment.

(Prior art) Generally, polyurethane distomers are synthesized mainly from polyisocyanates, polyols, and chain extenders, but the polyol used in the largest amount is polypropylene glycol or its ethylene oxide modified product. .

The reason for this is that it is the cheapest, and since polypropylene glycol is a liquid at room temperature, it is extremely easy to handle when used, which means it has the advantage of good workability and excellent water resistance. be.

(Problems to be Solved by the Invention) However, since it has serious drawbacks such as poor heat resistance, weather resistance, mechanical properties, etc., it cannot be used in fields that require such performance.

Therefore, polyester-based polyols are used in such fields.

For example, polyester polyols synthesized from ethylene glycol and adipic acid, polyester polyols synthesized from 1,4-butylene glycol and adipic acid, and polycaprolactone polyols made from ε-caprola (chthone) are commonly used. It is used.

However, with the exception of ε-caprolactone polyester, ethylene glycol/adipic acid polyester polyols and 1,4-butylene glycol/adipic acid polyesters have a drawback of very poor water resistance. Further, these polyester polyols are generally waxy solids with a melting point of 40 to 60°C when the molecular weight is 1000 or more.

However, when used in applications that require flexibility, it is necessary to use a high molecular weight polyol, which means that the polyester polyol must be melted beforehand at room temperature or in the winter, and tanks, piping, etc. must be kept warm. It is extremely difficult to work with, and even if it is melted, it is difficult to handle due to its high viscosity.Furthermore, since the polyol is heated to melt it, the reaction rate with -insyanate is low. It has the disadvantages of a short pot life and being difficult to handle.

In addition, using a low molecular weight polyol with a molecular weight of 500 or less,
By using a method of reacting polyisocyanate corresponding to 0.2 to 0.6 of the theoretical corresponding amount, a soft polyurethane can be obtained with relatively good workability. However, the soft polyurethane produced by such a method has drawbacks such as insufficient formation of polymer chains due to the insufficient amount of incyanate, resulting in a decrease in elastic recovery rate, etc., and clumping.

The present inventors solved these problems and, as a result of various studies on polyurethane elastomers, which are soft and have an excellent elastic recovery rate9, and also have good workability during production,
The desired product can be obtained by mixing a low melting point trifunctional polyol or a low melting point trifunctional polyol with a low melting point difunctional polyol in a specific ratio to form a polyurethane polymer chain with soft physical properties. The present invention was achieved based on the discovery that

(Structure of the Invention) That is, the present invention provides a polyester polyol resin synthesized from a j-hydric alcohol, a polybasic acid or its anhydride, and C-caprolactone, in which 30 to 100% by weight of the polyhydric alcohol has side chains. A dihydric alcohol having 3 to 10 carbon atoms, containing 30 to 80% by weight of ε-caprolactone, and a polyester polyol resin having a molecular weight of 1,000 to 10,000 and having a melting point of 30°C or less, and a polyhydric alcohol. 30 of them
~100% by weight is a trihydric alcohol having 3 to 10 carbon atoms with a side chain, contains 30 to 80% by weight of ε-caprolactone, has a melting point of 30°C or less, and has a molecular weight of 500 to 100.
This is a polyurethane elastomer resin consisting of a polyester polyol resin of 0.00% polyester polyol resin and polyisocyanate, and is characterized by a hardness of 10 to 50 degrees.

Among the polyhydric alcohols used as raw materials for the polyester polyol used in the present invention, the polyhydric alcohols having 3 to 10 carbon atoms and having side chains include 1.2-propylene glycol, 1.3-7"f Pentyl glycol, hydroxypivalate ester of neopentyl glycol, 2-methyl-1.37'ropanediol, 2.

3,5-trimethylbentanediol, trimethylolpropane, trimethylolethane, etc. can be used. Polyhydric alcohols without side chains that can be used in the range of 0 to 70% by weight include ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butylene diol, 1,5-bentanediol, 1,6-hexanediol etc. can be used.

If the amount of the polyhydric alcohol having 3 to 10 carbon atoms having a side chain is less than 30% by weight, it is not preferable because the melting point of the polyester polyol used in the present invention becomes high.

The polybasic acids or anhydrides thereof that are the second component of the polyester polyol used in the present invention include maleic acid, succinic acid, fumaric acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, phthalic acid, and isophthalic acid. , terephthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, trimellitic acid, or anhydrides thereof, etc., but it is particularly preferable to use adipic acid. Preferred for the purpose of obtaining melting point resins.

The third component, ε-caprolactone, is industrially produced by oxidizing cyclohexanone with a peracid such as hydrogen peroxide or peracetic acid in Bayer-Billiker reactors (1) and 2. In the present invention, it is necessary to contain ε-caprolactone in an amount of 30 to 80% by weight in the resin.

When the amount of ε-caprolactone is less than 30% by weight and 1J, the water resistance and low-temperature properties of the produced resin deteriorate. If the amount is more than 80% by weight, the melting point of the polyester will become 30° C. or higher due to the crystallinity of polycaprolactone, which is not preferable. In the present invention, oxycaproic acid, which is a ring-opened product thereof, can be used instead of ε-caprolactone. It is also possible to copolymerize other lactones.

The molecular weight of the bifunctional polyester polyol resin used in the present invention is from 1000 to 1oooo, preferably from 2000 to
It is 5000. The molecular weight of the trifunctional polyester polyol resin is 500 to 10,000, preferably 100.
It is 0-6000. This is because having a molecular weight in this range is convenient when applied to polyurethane elastomers.

Now, a method for synthesizing the polyester polyol used in the present invention will be described. The most basic method is to first synthesize a polyester polyol with a terminal hydroxyl group from a polyhydric alcohol and a polybasic acid, then ring-opening polymerize ε-caprolactone to the hydroxyl group to synthesize a lactone craft polyester polyol, and then synthesize the polyester polyol at a high temperature. This is a method of producing a random copolymerized polyester polyol of polybasic acid/polyhydric alcohol/lactone by causing a transesterification reaction between a basic acid ester chain and a polycaprolactone chain.

At this time, it is difficult to effectively lower the melting point if the block copolymer is used as is. Therefore, in order to synthesize a lactone-modified polyester polyol with a low melting point, it is necessary to cause a sufficient transesterification reaction to form a random copolymer as described above.

Therefore, the synthesis reaction of the polyester polyol used in the present invention basically consists of (1) an esterification reaction by dehydration from a polybasic acid and a polyhydric alcohol, and (2) an ε-
Ring-opening reaction of caprolactone, (3) Reaction in which ε-caprolactone is ring-opened by ester-forming water to become oxycarlonic acid, and further undergoes dehydration and esterification with hydroxyl groups and carboxyl groups, (4) Intra- and intermolecular esters of polyester It consists of four exchange reactions.

Therefore, the resin used in the present invention can also be obtained by mixing and heating separately synthesized polyester polyol and polycaprolactone polyol to cause a transesterification reaction. In addition, polybasic acids, polyhydric alcohols,
It can also be synthesized by simultaneously charging ε-caprolactone into a reactor and reacting it. At the same time,
The most preferred method is to use polyhydric alcohols and polybasic acids.
First, a polyester polyol with a small molecular weight is synthesized, and then e-caprolactone is graft-polymerized and a transesterification reaction is caused. This is because the reaction of synthesizing polyester polyol from polyhydric alcohol and polybasic acid takes the most time, and in this case, the reaction time is shorter for polyester polyols with smaller molecular weights.

The reaction temperature is 130°C to 240°C, preferably 140°C to 240°C.
The temperature is 30°C. Also, passing an inert gas such as nitrogen gas during the reaction gives good results on the color of the resin, etc. 1 In this reaction, titanium compounds such as tetrabutyl titanate and tetrabutyl titanate, dibutyltin laurate, tin octylate, diptyltin oxide 0, stannous chloride, and stannous bromide are used as ring-opening reaction catalysts for caprolactone.
The amount of tin, stannous iodide, etc. is 0.1 to 50 ppm, preferably 0.1 to 10 ppm. Furthermore, among these catalysts, titanium-based compounds in particular exhibit sufficient catalytic activity for the ester father conversion reaction.

In the present invention, the polyester diol and polyester triol obtained as described above are
It is used by mixing at a ratio of ~9 o/i 0 (molti). In particular, a range of 20/80 to 80/20 (molti) is suitable. Outside this range, the polyurethane entomer loses its flexibility, and its strength and heat resistance decrease, making it unusable for practical use.

Examples of the polyisocyanate used in the present invention include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and mixtures thereof (TDI). Diphenylmethane-4,4'-diincyanate (MDI)
, naphthalene-1,5-diisocyanate (NDI),
3,3'dimethyl-4,4'-biphenylene diisocyanate (TODI) xylylene diisocyanate (XD
I-), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), inphorone diincyanate (IPDI), hexamethylene diincyanate (H
DI ), hydrogenated xylylene diisocyanate (HXD
), crude TDI, polymethylene polyphenylisocyanate (crude MDi), and isocyanurate-modified products, carbodiimidation-modified products, and biuret-modified products of these isocyanates.

The amount of polyisocyanate used is the NCO contained therein.
The amount of groups is relative to the total amount of OH groups contained in the polyol,
Equivalent ratio of 0.6 to 1.2, more preferably 0.7 to 1.
If the ratio is above this range, the polyurethane elastomer will not lose its flexibility, and if it is below this range, the physical properties of the polyurethane elastomer will deteriorate.

These isocyanates may be used alone or in combination of two or more.

The present invention will be further explained by giving examples below, but the present invention is not limited by these.

Example Chubu means parts by weight.

Synthesis Example 1゜Adipic acid, 2259 parts, neopentyl glycol 20
22 parts of ε-caprolactone, 1950 parts of ε-caprolactone, and 11 parts of tetrabutyl titanate.
After stirring for 0 hours, dehydration esterification reaction, ring-opening polymerization of ε-caprolactone, and esterification reaction were carried out, and the acid value was 0.3.
A polyester polyol having a KOH■/f and a hydroxyl value of 44 KO)Iq/f was obtained. The melting point of this product was 0-5°C.

Synthesis Example 2゜1944 parts of adipic acid, 1552 parts of diethylene glycol
1, 446 parts of trimethylolpropane, 6,666 parts of ε-caprolactone, and 446 parts of tetrabutyl titanate were charged and stirred at 140°C to 220°C for 50 hours to carry out dehydration esterification reaction, ring-opening polymerization of ε-caprolactone, and transesterification reaction. conducted, acid value 0.2KOH1NI/r, hydroxyl value 69KOHη/? A polyester polyol was obtained. The melting point of this product was 5 to 10°C. 1. Example 1 A mixture of 500 parts of the polyester polyol obtained in Synthesis Example 1 and 500 parts of the polyester polyol obtained in Synthesis Example 2 was heated and stirred under reduced pressure. , Millionate MTL (carbodiimide modified MDI manufactured by Nippon Polyurethane) 106
t (equivalence ratio 0.8) and poured into a mold heated to 100°C. After heating this at 100° C. for 3 hr, the cured nidistomer was taken out from the mold. The obtained polyurethane elastomer had a hardness of A20, a 100% modulus of 3.7 kp/cd, a breaking strength of 561 w/J, a breaking elongation of 805 inches, and a rebound modulus of 32%.

Example 2゜1000 parts of the polyester polyol obtained in Synthesis Example 2 was heated and stirred under reduced pressure, and then Millionate MTL (carbodiimide-modified MDI manufactured by Nippon Polyurethane) was added at 115F (equivalence ratio 0.7) and heated to 100°C. injected into.

After heating this at 100°C for 3 hours, the cured elastomer was taken out from the mold.

The obtained polyurethane elastomer has a hardness of A'33° and a 100% modulus of 5.31c/! lI, breaking strength 21
The V-1 elongation at break was 543 cm, and the impact resilience was 35%.

Example 3゜900 parts of the polyester polyol obtained in Synthesis Example 1 and 100 parts of the polyester polyol obtained in Synthesis Example 2 were heated and stirred under reduced pressure, and a mixture obtained was mixed with MTL (Carbodiimide-modified MDI manufactured by Nippon Polyurethane). 862 (
(equivalence ratio 0.8) and poured into a mold heated to 100°C. After heating this at 100° C. far, the cured elastomer was taken out from the mold. The obtained polyurethane elastomer has a hardness of A18.100 and a hardness of 3.0 k.
e/J, breaking strength of 45 h/J, breaking elongation of 815 inches, and rebound modulus of 30 inches.

Claims (1)

[Scope of Claims] In a polyester polyol resin synthesized from a polyhydric alcohol, a polybasic acid or its anhydride, and ε-caprolactone, 30 to 100% by weight of the polyhydric alcohol has 3 carbon atoms and a side chain. ~10 dihydric alcohol, containing 30~80% by weight of ε-caprolactone, 0~90 mol% of a polyester polyol resin with a molecular weight of 1000~10000 having a melting point of 30°C or less, and 30~100% of the polyhydric alcohol. 100 to 10 mol % of a polyester polyol resin having a molecular weight of 50 to 10,000 and having a melting point of 30° C. or less, which is a trihydric alcohol having 3 to 10 carbon atoms and has a side chain, and contains 30 to 80 mol % of ε-caprolactone. It is made of polyester polyol resin and polyisocyanate, and its hardness is 10 to 50.
A polyurethane elastomer that is characterized by its hardness.