JP7296807B2 - Polyurethane - Google Patents

Description

The present invention relates to polyurethanes. More particularly, the present invention relates to polyurethanes having mechanical properties suitable for injection molding and excellent water resistance.

Polyurethane materials using hydroxyl-modified polybutadiene and diisocyanate compounds are known.
In Patent Document 1, 1 to 20 parts by weight of calcined PTFE powder is blended per 100 parts by weight of cast polyurethane elastomer obtained by reacting a urethane prepolymer obtained by reacting a polyol and an isocyanate with a chain extender. A polyurethane elastomer composition comprising Various polyols such as 1,4-polybutadiene-based and 1,2-polybutadiene-based polyols are exemplified as polyols.
Patent Document 2 describes a polymer characterized by containing a polyurethane-based resin obtained by reacting a polyol containing at least a portion of polybutadiene diol or a hydrogenated compound thereof, a polyisocyanate, and a chain extender, and a polyolefin-based resin. alloys are mentioned.
U.S. Pat. No. 5,300,000 describes a polyurethane composition comprising a polyurethane prepolymer cured with a slow-reacting curing agent selected from the group consisting of slow-reacting polyamines and difunctional glycols. The polyurethane prepolymer is then described as being prepared from a diisocyanate and a polyol. Examples of the polyol include polybutadiene glycol.
US Pat. No. 5,300,003 describes an article comprising two chemically grafted polymer layers, including a hydrogel layer and an end-functionalized polyurethane layer. The polyurethanes are described as containing soft segments such as hydroxy-terminated butadiene.

JP 2009-120722 A JP-A-6-184367 JP-A-4-241881 Special Table No. 2011-530336

Conventionally known polyurethanes sometimes have problems in that their mechanical properties are not suitable for injection molding and that they have poor water resistance. An object of the present invention is to provide a polyurethane having mechanical properties suitable for injection molding and excellent water resistance.

As a result of intensive studies by the present inventors in order to solve the above problems, polybutadiene having a molar ratio of 1,2-structure/1,4-structure of 55/45 to 95/5 and having hydroxyl groups at both ends, It was found that by reacting 3,3'-dimethyl-4,4'-biphenylene diisocyanate with a chain extender, a polyurethane having mechanical properties suitable for injection molding and excellent water resistance can be obtained. The present invention has been completed through further studies based on these findings.
That is, the present invention includes the following aspects.

(1) Polybutadiene-derived structure having a molar ratio of 1,2-structure/1,4-structure of 55/45 to 95/5 and hydroxyl groups at both ends, 3,3′-dimethyl-4,4′- A polyurethane containing a structure derived from biphenylene diisocyanate and a structure derived from a chain extender.
(2) The polyurethane according to (1), wherein the polybutadiene has a number average molecular weight (Mn) of 500 to 10,000.
(3) The polyurethane according to (1) or (2), wherein the chain extender is an aliphatic glycol.

The polyurethane of the present invention has mechanical properties suitable for injection molding and excellent water resistance.

The polyurethane according to the present invention is obtained by reacting polybutadiene having hydroxyl groups at both ends, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, and a chain extender.
As a result, the polyurethane according to the present invention has a polybutadiene-derived structure having a molar ratio of 1,2-structure/1,4-structure of 55/45 to 95/5 and having hydroxyl groups at both ends, 3,3′- It contains a structure derived from dimethyl-4,4'-biphenylene diisocyanate and a structure derived from a chain extender. Each structural unit is linked by well-known bonding modes in polyurethane production.

(Polybutadiene having hydroxyl groups at both ends)
Polybutadiene having hydroxyl groups at both ends preferably has a 1,2-structure/1,4-structure molar ratio of 55/45 to 95/5, more preferably 70/30 to 95/5. The molar ratio of 1,2-structure/1,4-structure can be calculated by measuring with ¹ H-NMR, for example. A method for adjusting the molar ratio of 1,2-structure/1,4-structure can be carried out by a known method. For example, the molar ratio of 1,2-structure/1,4-structure can be controlled by selecting the type of catalyst and auxiliary materials for polymerization used in the polymerization of butadiene.
All or part of the double bonds in polybutadiene having hydroxyl groups at both ends may be hydrogenated. Preferably, the double bonds in polybutadiene having hydroxyl groups at both ends are not hydrogenated.
Further, the number average molecular weight (Mn) of the polybutadiene component is preferably 500-10,000, more preferably 1,000-7,000. The number average molecular weight (Mn) is measured by gel permeation chromatography (GPC) using polystyrene as a standard substance. The measurement conditions were: mobile phase THF (tetrahydrofuran), mobile phase flow rate 1 mL/min, column temperature 40° C., sample injection amount 40 μL, sample concentration 2% by weight.
A commercially available product can be used as the polybutadiene having hydroxyl groups at both ends. Specifically, Nisso-PB-G-1000 (manufactured by Nippon Soda Co., Ltd.), Nisso-PB-G-2000 (manufactured by Nippon Soda Co., Ltd.), Nisso-PB-G-3000 (manufactured by Nippon Soda Co., Ltd.), Nisso-PB -GI-1000 (manufactured by Nippon Soda Co., Ltd.), Nisso-PB-GI-2000 (manufactured by Nippon Soda Co., Ltd.), Nisso-PB-GI-3000 (manufactured by Nippon Soda Co., Ltd.), and the like. These can be used individually by 1 type or in combination of 2 or more types.

（１） (3,3'-dimethyl-4,4'-biphenylene diisocyanate)
3,3′-dimethyl-4,4′-biphenylene diisocyanate (hereinafter sometimes referred to as TODI) used in the present invention is a compound represented by the following formula (1).

(1)

TODI can use a commercial item. Specifically, TODI manufactured by Nippon Soda Co., Ltd. can be mentioned.
The amount of TODI used during the reaction is set so that the R ratio value is preferably 1 to 10, more preferably 2 to 5, and still more preferably 2.1 to 3.8. The R ratio is the ratio of the number of moles of isocyanato groups derived from TODI to the number of moles of hydroxyl groups derived from polybutadiene having hydroxyl groups at both ends.

(chain extender)
The chain extenders used in the present invention are mainly low-molecular-weight polyols or low-molecular-weight polyamines, preferably low-molecular-weight polyols.

Low-molecular-weight polyols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-2- Propyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, 1,2-butanediol, 1,3- butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2,2, 4-trimethyl-1,3-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,8- Aliphatic glycols such as octanediol, 2-methyl-1,8-octanediol and 1,9-nonanediol; alicyclic glycols such as bis(hydroxymethyl)cyclohexane; xylylene glycol and bis(hydroxyethoxy)benzene, etc. and a glycol having an aromatic ring of Among these, aliphatic glycols or alicyclic glycols are preferred, and aliphatic glycols having 2 to 2 carbon atoms are preferred, from the viewpoint of obtaining a polyurethane having excellent mechanical strength, water resistance and handleability suitable for injection molding. Aliphatic glycols of 5 are even more preferred, with butanediol being particularly preferred.

Low-molecular-weight polyamines include aromatic diamines such as 2,4-tolylenediamine, 2,6-tolylenediamine, xylylenediamine, 4,4′-diphenylmethanediamine; ethylenediamine, 1,2-propylenediamine, 2, 2-dimethyl-1,3-propanediamine, 1,3-pentanediamine, 2-methyl-1,5-pentanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,6-hexanediamine , 2,2,4- or 2,4,4-trimethylhexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine; 1-amino-3-amino Alicyclics such as methyl-3,5,5-trimethylcyclohexane, 4,4'-dicyclohexylmethanediamine, isopropylidenecyclohexyl-4,4'-diamine, 1,4-diaminocyclohexane, and 1,3-bisaminomethylcyclohexane group diamines and the like. Among these, ethylenediamine, propylenediamine, 1,3-pentanediamine, or 2-methyl-1,5-pentanediamine is preferred.

The amount of the chain extender used during the reaction is such that the NCO index value is preferably 0.2 to 10, more preferably 0.5 to 1.25, and still more preferably 0.9 to 1.1. set. The NCO index is the ratio of the number of moles of isocyanato groups derived from TODI to the total number of moles of hydroxyl groups derived from polybutadiene having hydroxyl groups at both ends and hydroxyl groups derived from the chain extender.

(Method for producing polyurethane)
The polyurethane according to the present invention is not particularly limited in its production method, and can be produced, for example, by a prepolymer method or a one-shot method, but is preferably produced by a one-shot method.
In the prepolymer method, polybutadiene having hydroxyl groups at both ends is first reacted with TODI to obtain a urethane prepolymer having terminal isocyanato groups, which is then reacted with a chain extender to obtain polyurethane. The one-shot method is a method in which polybutadiene having hydroxyl groups at both ends, TODI, and a chain extender are added almost simultaneously to a reactor and reacted to obtain a polyurethane.
The reaction can be carried out by raising the temperature of the reactants until they reach a viscosity that allows the reactants to be sufficiently stirred. A specific temperature during the reaction is preferably room temperature to 120°C, more preferably 60 to 100°C. If the temperature during the reaction is too low, the reaction tends to proceed slowly and the time required for production tends to be long. If the temperature during the reaction is too high, side reactions may occur or the pot life may be shortened, which tends to make molding processing difficult.
The reaction can be carried out without solvent or in solvent. As the solvent, it is preferable to use one that is inert to the reaction. Examples of solvents include toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, dimethylformamide, tetrahydrofuran and the like.

A catalyst can be used in the polyurethane synthesis reaction. Examples of catalysts include tertiary amines such as dimethylethanolamine, triethylenediamine, tetramethylpropanediamine, tetramethylhexamethylenediamine, and dimethylcyclohexylamine, and metal catalysts such as stannous octate, potassium octylate, and dibutyltin dilaurate. etc. can be mentioned. The amount of catalyst used is preferably 1 to 1000 ppm, more preferably 5 to 800 ppm, based on the total amount of polybutadiene having hydroxyl groups at both ends, TODI and chain extender. If the amount of catalyst used is too small, the reaction will be slow and the production time will be lengthened. If the amount of the catalyst used is too large, the heat generation is so intense that it is difficult to control the reaction, and in addition, a gelled product may be produced or a colored polyurethane may be obtained.
Other additives can be appropriately added to the polyurethane of the present invention within a range that does not impair the effects of the present invention. Other additives include flame retardants, deterioration inhibitors, plasticizers, and the like.

EXAMPLES The present invention will be described in detail below using examples, but the present invention is not limited to the scope of the examples.

Example 1 Production of Polyurethane A 500 mL separable flask was charged with 74.65 g of polybutadiene (NISSO-PB-G2000: manufactured by Nippon Soda Co., Ltd.) having hydroxyl groups at both ends, and the system was evacuated. After that, the mixture was stirred at a temperature of 80° C. to remove moisture in the system. Then, nitrogen was introduced into the system to normal pressure. Dehydrated 1,4-butanediol (manufactured by Tokyo Kasei Co., Ltd.) 3.54 g (NCO index = 1.05), followed by 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TODI: Nippon Soda Co., Ltd.) 21.81 g of the product) was charged, and the system was evacuated at 80° C. for 2 minutes. This mixture was poured into a Teflon (registered trademark) mold and pressed at 80° C. for 30 minutes. Further, the mixture was heated at 80° C. for 12 hours to obtain a polyurethane sheet.

Comparative Example 1 Production of Polyurethane A 500 mL separable flask was charged with 76.46 g of polytetramethylene glycol (PTMG: manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), and the system was evacuated. After that, the mixture was stirred at a temperature of 80° C. to remove moisture in the system. Then, nitrogen was introduced into the system to normal pressure. Dehydrated 1,4-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) 3.45 g (NCO index = 1.05), followed by 4,4'-methylenediphenyl diisocyanate (4,4'-MDI: Tokyo Kasei) (manufactured by Kogyo Co., Ltd.) was charged, and the system was evacuated at 80° C. for 2 minutes. This mixture was poured into a Teflon mold and pressed at 80° C. for 30 minutes. Further, the mixture was heated at 80° C. for 12 hours to obtain a polyurethane sheet.

Comparative Example 2 Production of Polyurethane A 500 mL separable flask was charged with 80.06 g of polytetramethylene glycol (PTMG: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and the system was evacuated. After that, the mixture was stirred at a temperature of 80° C. to remove moisture in the system. Then, nitrogen was introduced into the system to normal pressure. Dehydrated 1,4-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) 3.61 g (NCO index = 1.05), followed by 1,3-bis(isocyanatomethyl)cyclohexane (H-XDI: Tokyo Chemical Industry Co., Ltd.) 16.33 g of the product) was charged, and the system was evacuated at 80° C. for 2 minutes. This mixture was poured into a Teflon mold and pressed at 80° C. for 30 minutes. Further, the mixture was heated at 80° C. for 12 hours to obtain a polyurethane sheet.

Comparative Example 3 Production of Polyurethane A 500 mL separable flask was charged with 75.61 g of polytetramethylene glycol (PTMG: manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), and the system was evacuated. After that, the mixture was stirred at a temperature of 80° C. to remove moisture in the system. Then, nitrogen was introduced into the system to normal pressure. Dehydrated 1,4-butanediol (manufactured by Tokyo Kasei Co., Ltd.) 3.41 g (NCO index = 1.05), followed by 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TODI: Nippon Soda Co., Ltd.) 20.98 g of the product) was charged, and the system was evacuated at 80° C. for 2 minutes. This mixture was poured into a Teflon mold and pressed at 80° C. for 30 minutes. Further, the mixture was heated at 80° C. for 12 hours to obtain a polyurethane sheet.

Comparative Example 4 Production of Polyurethane A 500 mL separable flask was charged with 79.00 g of polytetramethylene glycol (PTMG: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and the system was evacuated. After that, the mixture was stirred at a temperature of 80° C. to remove moisture in the system. Then, nitrogen was introduced into the system to normal pressure. 3.56 g of dehydrated 1,4-butanediol (manufactured by Tokyo Kasei Co., Ltd.) (NCO index = 1.05) and then 17.44 g of 1,5-diisocyanatonaphthalene (NDI: manufactured by Nippon Soda Co., Ltd.) were added thereto. After charging, the system was evacuated at 80° C. for 2 minutes. This mixture was poured into a Teflon mold and pressed at 80° C. for 30 minutes. Further, the mixture was heated at 80° C. for 12 hours to obtain a polyurethane sheet.

Comparative Example 5 Production of Polyurethane A 500 mL separable flask was charged with 75.53 g of polybutadiene having hydroxyl groups at both ends (NISSO-PB-G2000: manufactured by Nippon Soda Co., Ltd.), and the pressure in the system was reduced. After that, the mixture was stirred at a temperature of 80° C. to remove moisture in the system. Then, nitrogen was introduced into the system to normal pressure. To this, 3.58 g of dehydrated 1,4-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) (NCO index = 1.05), followed by 4,4'-methylenediphenyl diisocyanate (4,4'-MDI: Tokyo Chemical Industry Co., Ltd.) 20.89 g (manufactured by Co., Ltd.) was charged, and the system was evacuated at 80° C. for 2 minutes. This mixture was poured into a Teflon mold and pressed at 80° C. for 30 minutes. Further, the mixture was heated at 80° C. for 12 hours to obtain a polyurethane sheet.

Comparative Example 6 Production of Polyurethane A 500 mL separable flask was charged with 75.53 g of polybutadiene (NISSO-PB-G2000: manufactured by Nippon Soda Co., Ltd.) having hydroxyl groups at both ends, and the system was evacuated. After that, the mixture was stirred at a temperature of 80° C. to remove moisture in the system. Then, nitrogen was introduced into the system to normal pressure. Dehydrated 1,4-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) 3.76 g (NCO index = 1.05), followed by 1,3-bis (isocyanatomethyl) cyclohexane (H-XDI: Tokyo Chemical Industry Co., Ltd.) 17.01 g of the product) was charged, and the system was evacuated at 80° C. for 2 minutes. This mixture was poured into a Teflon mold and pressed at 80° C. for 30 minutes. Further, the mixture was heated at 80° C. for 12 hours to obtain a polyurethane sheet.

Comparative Example 7 Production of Polyurethane A 500 mL separable flask was charged with 78.14 g of polybutadiene having hydroxyl groups at both ends (NISSO-PB-G2000: manufactured by Nippon Soda Co., Ltd.), and the system was evacuated. After that, the mixture was stirred at a temperature of 80° C. to remove moisture in the system. Then, nitrogen was introduced into the system to normal pressure. 3.71 g (NCO index = 1.05) of dehydrated 1,4-butanediol (manufactured by Tokyo Kasei Co., Ltd.) and then 18.15 g of 1,5-diisocyanatonaphthalene (NDI: manufactured by Nippon Soda Co., Ltd.) were added thereto. After charging, the system was evacuated at 80° C. for 2 minutes. This mixture was poured into a Teflon mold and pressed at 80° C. for 30 minutes. Further, the mixture was heated at 80° C. for 12 hours to obtain a polyurethane sheet.

(Evaluation of polyurethane)
The polyurethane sheets obtained in Example 1 and Comparative Examples 1 to 7 were each subjected to hardness test, tensile test, water absorption test, and compression set test. Table 1 shows the results.
<Hardness test>
Six molded sheets with a thickness of 2 mm were stacked, and hardness was measured according to JIS K 7311 using an A type or D type durometer (manufactured by Teclock).
<Tensile test>
A No. 5 dumbbell test piece was prepared according to JIS K 7312, and the modulus at 100% elongation (M100), the modulus at 300% elongation (M300), Tensile strength (stress at break) and elongation at break were measured. Test temperature 23°C, test speed 500 mm/min.
Gauge distance: 20 mm, Chuck distance: 50 mm
<Water absorption test>
A test piece of 50 mm×50 mm×2 mm thick was prepared according to JIS K 7209, and the mass W ₀ of the test piece was measured. It was immersed in water at 23° C. for 24 hours, pulled up, the water on the surface was wiped off, and the weight W ₁ of the test piece was measured again. The ratio of the increased mass W ₁ -W ₀ before and after immersion to the mass W ₀ before immersion (water absorption) was calculated.
<Compression set>
According to JIS K 7312, the molded sheet was processed to φ13 mm and stacked into three sheets. This was stored at 70 ° C. for 24 hours in a constant temperature bath at a compression ratio of 25%, and then the compression ratio (initial thickness - thickness after 30 minutes / initial thickness - added thickness ratio) was calculated. bottom.

Claims (3)

Structure derived from polybutadiene having a molar ratio of 1,2-structure/1,4-structure of 55/45 to 95/5 and hydroxyl groups at both ends, derived from 3,3′-dimethyl-4,4′-biphenylene diisocyanate and a structure derived from a chain extender, wherein the chain extender is at least one selected from aliphatic, alicyclic or aromatic glycols and aliphatic, alicyclic or aromatic diamines. 2. The polyurethane according to claim 1, wherein the polybutadiene has a number average molecular weight (Mn) of 500-10,000. 3. Polyurethane according to claim 1 or 2, wherein the chain extender is an aliphatic glycol.