JPH08104724A - Production of urethane prepolymer that remains liquid even at low temperature - Google Patents

Abstract

PURPOSE: To produce a urethane prepolymer having a lowered crystallization temperature by using a mixture of a polyether glycol with a poly(tetramethylene ether/3-methyl-methyltetramethylene ether) glycol as the dihydroxypolyol component. CONSTITUTION: A polyether comprising oxytetramethylene groups and having a molecular weight of 600-5000 is mixed with 1-50wt.% poly(tetramethylene ether/3-methyltetramethylene ether) glycol comprising oxytetramethylene groups of formula I and 5-40wt.% 3-methyl-oxytetramethylene groups of formula II (wherein R1 and R2 are each H or methyl) to prepare dihydroxypolyol component (A). Component A is mixed with an isocyanate compound (B) such as 2,4-tolylene diisocyanate in a B to A molar ratio of 1.2-2.5, and the mixture is reated at about 60-90 deg.C for about 2-5hr to obtain a urethane prepolymer prevented from crystallizing even at 10 deg.C or below.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyurethane prepolymer from a polyether or polyetherester polyol containing a tetrahydrofuran polymer segment used as a raw material for producing adhesives, paints, synthetic leather, etc. The present invention relates to a method for producing a urethane prepolymer having improved mixing properties of a cross-linking agent, a filler for modifying an elastomer, a colorant and the like by having a liquid property.

[0002]

2. Description of the Related Art Polyurethane prepolymers are chain-like polymers having a terminal isocyanate group obtained by reacting a diol compound with various aliphatic or aromatic diisocyanate compounds such as polyester glycol, polyether glycol and polycarbonate glycol in the presence of excess isocyanate. Obtained by forming a urethane compound

And these urethane prepolymers are
Depending on the application, it can be used as adhesives, paints, synthetic leather, etc. as urethane elastomers by performing chain extension with various diol compounds and diamine compounds, or with polyfunctional polyols for chain extension and curing reaction. ing.

Further, since the urethane prepolymer has a highly reactive and active isocyanate group at the terminal, hydroxyallyl compounds such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate and allyl alcohol, or acrylate compounds and glycidol. By adding an epoxy compound such as glycerol diglycidyl ether, it is used in the field of adhesives and paints as urethane acrylate and urethane epoxy resin.

As described above, a wide variety of prepolymers can be obtained by combining the type of polyol used and the type of isocyanate compound in the urethane prepolymer which can be a useful raw material as an elastomer material.
Among these raw materials, polytetramethylene ether glycol (PT
G) and tetrahydrofuran and ε-caprolactone,
γ-butyrolactone, polyol obtained by ring-opening copolymerization with ethylene oxide, propylene oxide or the like, or polyether obtained as a block copolymer with various glycols such as PTG and polyethylene ether glycol, polypropylene ether glycol, polybutylene adipate, or the like. Dihydroxy polyols selected from polyether ester polyols are widely used because they can produce elastomers having excellent abrasion resistance and wet heat resistance and good impact resilience.

Among such dihydroxy polyols,
When the molecular weight of the oxytetramethylene group contained in PTG and some copolymer polyols is 600 or less, it is possible to produce a urethane prepolymer having liquidity at a low temperature. However, these urethane prepolymers were used. In urethane elastomers, urethane acrylates, and urethane epoxy resins, the soft segment (molecular chain length of the polyol) is short, so it is possible to manufacture soft elastomers, paints, and coatings and leather with softness in synthetic leather. Have difficulty. On the other hand, the molecular weight of the oxytetramethylene group contained in the polyol is 60.
A urethane prepolymer obtained from a dihydroxypolyol exceeding 0 causes a remarkable thickening tendency and a crystallization phenomenon at low temperatures (10 ° C. or lower), and therefore a chain extender, a crosslinking agent,
Coloring agents, plasticizers, or various elastomer-modifying fillers have poor mixability, and uniform blends cannot be obtained, making it difficult to obtain elastomers with excellent mechanical properties.
In addition, it has drawbacks in workability when it is used as a paint or when manufacturing synthetic leather. In the case of a urethane prepolymer that easily causes such a thickening tendency and a crystallization phenomenon, in order to improve workability, by adding an organic solvent such as toluene, xylene, benzene, ethyl acetate, and methyl ethyl ketone and a plasticizer, Although it suppresses viscosity and prevents crystallization, these organic solvents
There is a problem that causes environmental pollution and impairs the health of workers.

[0007]

DISCLOSURE OF THE INVENTION The present invention is applicable to low temperature (10
When a urethane prepolymer is prepared using a dihydroxypolyol that is a polyether polyol and a polyetherester polyol containing an oxytetramethylene group that causes a crystallization phenomenon at (° C. or lower), a poly ( By using a polyol mixed with tetramethylene ether / 3-methyltetramethylene ether) glycol,
It is intended to provide a urethane prepolymer which does not cause a crystallization phenomenon even at 0 ° C or lower.

[0008]

In the present invention, the low temperature (1
A method for producing a urethane prepolymer that does not cause crystallization even at 0 ° C. or lower) is a dihydroxypolyol selected from an oxytetramethylene group-containing polyether polyol and a polyetherester polyol, and poly (tetramethylene ether / 3-methyl tetra). Obtained by reacting with an isocyanate compound using a polyol mixed with methylene ether) glycol.

That is, the present invention relates to a urethane prepolymer having an isocyanate group at the terminal, which is obtained from a dihydroxypolyol (A) and an isocyanate compound (B) by a urethanization reaction,

(A) The dihydroxypolyol has an oxytetramethylene group-containing molecular weight of 600 to 500.
0 polyol and poly (tetramethylene ether / 3) having the groups represented by formula (I) and formula (II) as constitutional units
-Methyltetramethylene ether) glycol and has the formula (I)

Embedded image Formula (II)

[Chemical 4] [Wherein R ₁ and R ₂ represent a hydrogen atom or a methyl group, and
_{One of 1} and R ₂ is a methyl group. ]

(B) Poly (tetramethylene ether) having a group represented by the formula (I) or the formula (II) as a constitutional unit.
The molecular weight of 3-methyltetramethylene ether) glycol is 500 to 5000, and the mixing ratio of poly (tetramethyleneether / 3-methyltetramethyleneether) glycol to the total dihydroxypolyol (A) is 1 to 50% by weight,

(C) Poly (tetramethylene ether / 3)
-Methyltetramethylene ether) The proportion of the structural unit of the formula (II) contained in glycol is 5 to 40% by weight,

(D) The total dihydroxypolyol (A) and the isocyanate compound are in a molar ratio (B / A) of 1.2-.
The present invention relates to a method for producing a urethane prepolymer obtained by reacting in the range of 2.5.

The polyol used in the present invention is a dihydroxypolyol selected from oxytetramethylene group-containing polyether polyols and polyether ester polyols. Known PTGs obtained by ring-opening polymerization of tetrahydrofuran and JP-A- 63-1050
No. 30, JP-A-63-178131, polyols containing an oxytetramethylene group by copolymerization of ε-caprolactone, γ-butyrolactone, ethylene oxide, propylene oxide and tetrahydrofuran, and JP-A No. 01- No. 252630 and JP-A No. 02-11628, which contain an oxytetramethylene group obtained by block or random copolymerization of tetrahydrofuran with various glycols such as polyethylene acylate, polypropylene acylate, and polybutylene adipate, which are obtained by the production method. Polyols can also be used. The molecular weight of these polyols is 6
It is from 00 to 5000, preferably from 800 to 2000.

The poly (tetramethylene ether / 3-methyltetramethylene ether) glycol used in the present invention is used as a crystallization inhibitor at low temperature and has the groups represented by the above formulas (I) and (II). As a constitutional unit, these polymerization modes are random copolymerization, and tetrahydrofuran and 3-methyltetrahydrofuran are converted into HClO ₄ , HSO ₃ F, HSO ₃ Cl, HBF.
Protonic acid such as ₄ or Et ₃ OBF ₄ , CH ₃
An ion complex such as COSbCl ₆ , C ₆ H ₅ N ₂ PF ₆ , and CH ₃ COCl-BF ₃ , SOCl ₂
Obtained by random copolymerization by -AlCl _3, POCl ₃ -FeCl tetrahydrofuran catalyst system alone or in combination with an anhydride or accelerators known polymerization disclosed agents as ring-opening polymerization catalyst such as _3.

The proportion of the constituent unit of the formula (II) contained in poly (tetramethylene ether / 3-methyltetramethylene ether) glycol is preferably 5 to 40% by weight, particularly 8 to 25% by weight. preferable.

This poly (tetramethylene ether / 3-
The molecular weight of (methyltetramethylene ether) glycol is 500 to 5,000, preferably 800 to 3,000. The mixing ratio of poly (tetramethylene ether / 3-methyltetramethylene ether) glycol having a group represented by the formula (I) and the formula (II) as a constituent unit to the total dihydroxypolyol (A) is 1 to 50% by weight. , Preferably 3 to 30% by weight.

The isocyanate compound used here is 4,4'-diphenylmethane diisocyanate,
2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and mixed tolylene diisocyanate of these 2,4,2,6, m-phenylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate,
1,4-hexylene diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy 4,
There are 4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, tetramethyl xylene diisocyanate and the like. And carbodiimide modified 4,
4'-diphenylmethane diisocyanate can also be used

The method for producing the urethane prepolymer has a molecular weight of 500 to 500 containing an oxytetramethylene group.
0 polyol and poly (tetramethylene ether / 3) having the groups represented by formula (I) and formula (II) as constitutional units
-Dihydroxypolyol (A), which is a mixture of -methyltetramethylene ether) glycol, and diisocyanate compound (B) in a molar ratio (B / A) of 1.2 to 2.5.
It is preferably 40 within a range of 1.5 to 2.0 with mixing and stirring.
It can be produced by carrying out the reaction at 120 to 120 ° C, preferably 60 to 90 ° C for 2 to 5 hours.

[0020]

Embodiments The contents will be described in detail below with reference to embodiments. The 3-methyltetramethylene ether unit in the examples represents the formula (II). Note 1 PTG in Table 1
-L represents poly (tetramethylene ether / 3-methyltetramethylene ether) glycol. Note 2 in Table 1, 2,4TDI means 2,4-tolylene diisocyanate, and MT means 4,4'-diphenylmethane diisocyanate. Note 3 NCO in Table 1
/ OH represents (molar ratio of used diisocyanate / used polyol alone or PTG-L mixed polyol).
The viscosity of the prepolymer of Note 4 in Table 1 was measured using a Bismetron rotational viscometer (model VA-1).

Example 1 A PTG-850SN was placed in a 300 ml separa flask equipped with a thermometer and a stirrer.
(Hodogaya Chemical Co., Ltd., polytetramethylene ether glycol molecular weight 850) 80.0 g, and poly (tetramethylene ether / 3-methyltetramethylene ether) glycol (3-methyltetramethylene ether) obtained by a known method. Unit 16% by weight, molecular weight 1
000) 20.0 g was weighed and dried under reduced pressure at 5 mmHg under heating and stirring at 100 ° C. for 2 hours. Then 80
The temperature was lowered to 0 ° C., 30.6 g of 2,4-tolylene diisocyanate (Coronate T-100 manufactured by Nippon Polyurethane Industry Co., Ltd.) was added under normal pressure, and the reaction was carried out for 3 hours to give a prepolymer having an isocyanate group at the end. A polymer (isocyanate / polyol molar ratio of 1.5) was obtained. Table 1 shows the measured viscosity value of this urethane prepolymer at low temperature (10 ° C.) and the presence or absence of crystallization.

[Example-2] Similar to Example-1, PT
G-850SN (90.0 g), poly (tetramethylene ether / 3-methyltetramethylene ether) glycol (containing 16% by weight of 3-methyltetramethylene ether unit, molecular weight 1000) 10 g, mixed polyol and 2,4-tolylene diisocyanate 30 A prepolymer having an isocyanate group at the end (isocyanate / polyol molar ratio of 1.5) was obtained from 0.8 g. Table 1 shows the measured viscosity value and the presence or absence of crystallization of this urethane prepolymer at a low temperature (10 ° C.).

[Embodiment 3] Similar to Embodiment 1, the PT
G-850SN (95.0 g), poly (tetramethylene ether / 3-methyltetramethylene ether) glycol (containing 16% by weight of 3-methyltetramethylene ether unit, molecular weight 1000) 5.0 g, mixed polyol and 2,4-tolylene diene A prepolymer having an isocyanate group at the end (isocyanate / polyol molar ratio of 1.5) was obtained from 31.0 g of isocyanate. Table 1 shows the measured viscosity value of this urethane prepolymer at low temperature (10 ° C.) and the presence or absence of crystallization.

[Embodiment 4] Similar to Embodiment 1, the PT
G-1000 (polytetramethylene ether glycol manufactured by Hodogaya Chemical Co., Ltd., molecular weight 1000) 96.
0 g and poly (tetramethylene ether / 3-methyltetramethylene ether) glycol (containing 16% by weight of 3-methyltetramethylene ether unit, molecular weight 100)
0) 24.0 g of mixed polyol, and 33.9 g of 2,4-tolylene diisocyanate gave a prepolymer having an isocyanate group at the end (isocyanate / polyol molar ratio of 1.6). Table 1 shows the measured viscosity value and the presence or absence of crystallization of this urethane prepolymer at a low temperature (10 ° C.).

[Embodiment-5] Similar to Embodiment-1, PT
A mixed polyol of G-1000, 108.0 g and poly (tetramethylene ether / 3-methyltetramethylene ether) glycol 12.0 g (containing 16% by weight of 3-methyltetramethylene ether unit, molecular weight 1000) and 2,4- Tolylene diisocyanate 33.9
From g, a prepolymer having an isocyanate group at the terminal (isocyanate / polyol molar ratio 1.6) was obtained. Table 1 shows the measured viscosity value and the presence or absence of crystallization of this urethane prepolymer at a low temperature (10 ° C.).

[Embodiment-6] In the same manner as in Embodiment-1, PT
G-1000, 97.0 g, a mixed polyol of poly (tetramethylene ether / 3-methyltetramethylene ether) glycol 3.0 g (containing 16% by weight of 3-methyltetramethylene ether unit, molecular weight 1000) and 2,4-tri A prepolymer having an isocyanate group at the terminal (isocyanate / polyol molar ratio of 2.0) was obtained from 34.7 g of diisocyanate. Table 1 shows the measured viscosity value and the presence or absence of crystallization of this urethane prepolymer at a low temperature (10 ° C.).

[Examples -7, -8, -9] In the same manner as in Example-1, PTG-2000 (polytetramethylene ether glycol manufactured by Hodogaya Chemical Co., Ltd., molecular weight 20)
70) containing poly (tetramethylene ether / 3-methyltetramethylene ether) glycol (3-methyltetramethylene ether unit 16% by weight, molecular weight 19
90) content of 50% by weight in the mixed polyol, 3
A mixed polyol is produced so that the amount becomes 0% and 10%,
A prepolymer having an isocyanate group at the terminal (isocyanate / polyol molar ratio of 2.0) was obtained from these mixed polyols and 2,4-tolylene diisocyanate. Table 1 shows the measured viscosity values of these urethane prepolymers at low temperature (10 ° C.) and the presence or absence of crystallization.

[Embodiment-10] As in Embodiment-1, P
97.0 g of TG-2000 (molecular weight 2070) and 3.0 g of poly (tetramethylene ether / 3-methyltetramethylene ether) glycol (containing 16% of 3-methyltetramethylene ether unit, molecular weight 1990), a mixed polyol of 2, and A prepolymer having an isocyanate group at the end (an isocyanate / polyol molar ratio of 2.0 was obtained from 16.9 g of 4-tolylene diisocyanate. The viscosity measurement value of this urethane prepolymer at low temperature (10 ° C.) and the presence or absence of crystallization were determined. The results are shown in Table 1.

[Examples-11, -12, -13] Similar to Example-1, as the polyols used in Examples-1, -2, -3, and the isocyanate added at the same mixed polyol ratio, Using 4,4'-diphenylmethane diisocyanate (Millionate MT manufactured by Nippon Polyurethane Industry Co., Ltd.), three types of prepolymers having an isocyanate group at the terminal (isocyanate / polyol molar ratio of 2.0) were obtained, and each of the examples was used. -11, -1
It was set to 2, -13. Table 1 shows the measured viscosity values of these urethane prepolymers at low temperature (10 ° C.) and the presence or absence of crystallization.
It was shown to.

[Comparative Example-1] In the same manner as in Example-1, PT
A prepolymer having an isocyanate group at the terminal (isocyanate / polyol molar ratio of 1.5) was obtained from G-850SN and 2,4-tolylene diisocyanate. Table 1 shows the measured viscosity value and the presence or absence of crystallization of this urethane prepolymer at a low temperature (10 ° C.).

Comparative Example-2 In the same manner as in Example-1, from the polyol and isocyanate used in Comparative Example-1,
A prepolymer having an isocyanate group at the terminal (isocyanate / polyol molar ratio 2.0) was obtained. Table 1 shows the measured viscosity value and the presence or absence of crystallization of this urethane prepolymer at a low temperature (10 ° C.).

[Comparative Example-3] PT as in Example-1
Prepolymer having an isocyanate group at the terminal from G-850SN and 4,4'-diphenylmethane diisocyanate (isocyanate / polyol molar ratio 2.0)
I got Table 1 shows the measured viscosity value and the presence or absence of crystallization of this urethane prepolymer at a low temperature (10 ° C.).

[Comparative Example-4] Similar to Example-1, PT
A prepolymer having an isocyanate group at the terminal (isocyanate / polyol molar ratio of 2.0) was obtained from G-2000 and 2,4'-tolylene diisocyanate. Table 1 shows the measured viscosity value and the presence or absence of crystallization of this urethane prepolymer at a low temperature (10 ° C.).

[0034]

[Table 1]

[0035]

EFFECTS OF THE INVENTION Since the urethane prepolymer obtained by the present invention has liquidity even at a low temperature of 10 ° C. or lower, workability when mixing a chain extender, a cross-linking agent, a filler for modifying an elastomer, etc. is improved. Be improved.

Claims (1)

[Claims] 1. A urethane prepolymer having an isocyanate group at a terminal, which is obtained from a dihydroxypolyol (A) and an isocyanate compound (B) by a urethanization reaction, wherein (a) the dihydroxypolyol contains an oxytetramethylene group. Of 600 to 5000, and poly (tetramethylene ether / 3-methyltetramethylene having oxytetramethylene group and 3-methyloxytetramethylene group represented by the formulas (I) and (II) as constitutional units. Ether) glycol mixture of formula (I) Formula (II) embedded image [Wherein R ₁ and R ₂ represent a hydrogen atom or a methyl group,
One of R ₁ and R ₂ is a methyl group. ] (B) The molecular weight of poly (tetramethylene ether / 3-methyltetramethylene ether) glycol having the groups represented by the formulas (I) and (II) as a constitutional unit is 50.
0 to 5000, and the mixing ratio of poly (tetramethylene ether / 3-methyltetramethylene ether) glycol to the total dihydroxy polyol (A) is 1 to 50.
% Of the formula (II) contained in (c) poly (tetramethylene ether / 3-methyltetramethylene ether) glycol.
(D) The total dihydroxypolyol (A) and the isocyanate compound (B) react in a molar ratio (B / A) of 1.2 to 2.5. A method for producing a urethane prepolymer obtained by the method.