JP3518791B2 - Kneaded polyurethane composition and polyurethane molded article using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a kneading type polyurethane in which hydrolysis resistance is significantly improved while maintaining the original strength of polyurethane, and a polyurethane roll and belt using the same. It is suitable for use as a driving belt, various conveying rolls and driving rolls.

[0002]

2. Description of the Related Art Polyurethanes are classified into casting type, kneading type, thermoplastic type and the like depending on the molding method. Among them, the cast type is generally used because of its excellent various characteristics. On the other hand, the kneading type has an advantage that general rubber processing equipment such as a rubber kneading open roll and a press can be used.

[0003]

However, the kneading type polyurethane has a problem that it is inferior in hydrolysis resistance as compared with the casting type polyurethane. In addition, there is a problem in that the mechanical strength is reduced when trying to improve the hydrolyzability.

Therefore, the present invention has been made in view of such circumstances.
A kneading type polyurethane that can use general rubber processing equipment, but is superior in hydrolysis resistance and mechanical strength as compared with conventional ones, and a polyurethane molded article using the same This is an issue.

[0005]

Means for Solving the Problems] A first aspect of the present invention to achieve the object described above is kneaded polyurethane resulting from the reaction of polyol and polyisocyanate, this kneading type
Kneading-type polyure containing a curing agent for crosslinking polyurethane
A tongue composition, wherein the polyol is polycarbonate
Diols, polyether diols and polyesters
At least one polymerization initiator R selected from diols
Obtained by reacting ₁ (OH) ₂ with ε-caprolactone
That the poly -ε- caprolactone based diol represented by the following formula (I) as the main component, it is and manufactured to the formulation molecular weight distribution of the ε- caprolactone chain portion is narrower caprolactone
The average value of the ton chain is controlled to 8 or less, and the poly-ε-
Of the caprolactone chain portion of the caprolactone-based diol
The molecular weight distribution Mw / Mn is 1.0 to 1.5,
Isocyanate unit and the R ₁ containing urethane bonds
The crystallinity of the caprolactone chain is hindered by the effect of
In a kneading-type polyurethane composition which is characterized in that what is.

[0006]

[Chemical 3] (Here, [] indicates a caprolactone chain portion, and m
And n represent the number of chains, and R ₁ is a polymerization initiator R ₁ (O
H) ₂ and R ₁ (OH) ₂ has a molecular weight distribution)
A second aspect of the present invention, in the first embodiment, the curing
The agents are organic peroxides, sulfur, organic sulfur-containing compounds and
A kneading-type polyurethane composition is characterized by being at least one selected from a cyanate compound .

A third aspect of the present invention is the first or second aspect.
In the above, the poly-ε-caprolactone-based diol
From SnCl ₂ and a tin catalyst represented by the following formula (II)
Manufactured under reaction conditions of 150 ° C or less using selected catalyst
Kneading type polyurethane characterized in that
In composition.

[0008]

[Chemical 4]

(Wherein R ₂ is hydrogen, an alkyl group or
Is an aryl group, X is a hydroxyl group, an alkoxide group or a fluorine group.
Indicates halogen other than elementary)

A fourth aspect of the present invention is any one of the first to third aspects.
In the above embodiment, the average value of the caprolactone chain is 3
Kneading type porosity characterized by being controlled in the range of
It is in a polyurethane composition.

A fifth aspect of the present invention is any one of the first to fourth aspects.
In the above embodiment, the polyisocyanate is 2,6-
Toluene diisocyanate (TDI), 4,4 '- diphenyl
Phenyl methane diisocyanate (MDI), parapheny
Diisocyanate (PPDI), 1,5-naphthalene
Diisocyanate (NDI) and 3,3-dimethyldi
Phenyl-4,4 '- or diisocyanate (TODI)
Kneading characterized by being at least one selected from
Type polyurethane composition.

A sixth aspect of the present invention is any one of the first to fifth aspects.
In one embodiment, ε-caprolactone in all polyols
Characterized in that the unit content is 30% by weight or more
Kneading type polyurethane composition.

A seventh aspect of the present invention is any one of the first to sixth aspects.
In one embodiment, the glass transition of the kneading-type polyurethane
Kneading characterized in that the temperature Tg is -20 ° C or lower
Type polyurethane composition.

An eighth aspect of the present invention is any one of the first to seventh aspects.
The kneading-type polyurethane composition described in 1.
In polyurethane molded body characterized by that.

The structure of the present invention will be described in detail below.

The kneading type polyurethane used in the present invention is
It can be obtained by reacting a polyol and a polyisocyanate.

Here, the polyol used in the present invention uses poly-ε-caprolactone type diol as a main component. Here, the poly-ε-caprolactone diol is obtained by ring-opening polymerization of ε-caprolactone in the presence of a polymerization initiator having active hydrogen, and can be represented by the above formula (I). In the present invention, among them, ε-
A product produced by a formulation in which the molecular weight distribution of the caprolactone chain portion is narrowed is used.

By using such a poly-ε-caprolactone-based diol, it is possible to freely formulate even in a range where it could not be used because of its strong crystallinity, and to obtain a hydrolysis resistance which is unprecedented. be able to.

Further, when producing such a poly-ε-caprolactone-based diol, it is known that the molecular weight distribution of the ε-caprolactone chain part is regulated by the selection of the polymerization catalyst and the reaction conditions such as the polymerization temperature. However, in particular, a catalyst selected from SnCl ₂ and the tin-based catalyst represented by the general formula (II) described above, for example, monobutyltin oxide or tin halide excluding fluorine is preferably used, and the temperature is preferably 150 ° C. or lower. Suitable poly-amines for use in the invention by being prepared by polymerizing under conditions.
An ε-caprolactone diol can be produced. The catalysts exemplified above are suitable for producing a poly-ε-caprolactone diol having a narrow molecular weight distribution, but the catalysts are not limited thereto.

The average value of the caprolactone chain (average value of m and n below) in the poly-ε-caprolactone diol used in the present invention is 8 or less, preferably 3 to.
It is preferable to use a very limited range of 8 and a molecular weight distribution Mw / Mn of the caprolactone chain portion of 1.0 to 1.5 or less.

Thus, the average number of caprolactone chains of the poly-ε-caprolactone diol used in the present invention is 8
In the following, particularly, 3 to 8 means that in the kneading type polyurethane of the present invention comprising a caprolactone chain portion and a polyurethane bond, the caprolactone chain portion, which originally has strong crystallinity, has a urethane bond in a normal state where no strong stress is applied. Isocyanate unit constituting and the above formula (I)
The effect of R ₁ is that it becomes amorphous and maintains elasticity as a whole, and exhibits elasticity. However, in an abnormal state in which it is destroyed by a force such as tension, the caprolactone chain part is oriented in the original orientation. This is because the reversible state of exhibiting crystallinity and contributing to strength is maintained. Further, setting the molecular weight distribution Mw / Mn of the caprolactone chain portion to 1.5 or less is intended to limit the amount of caprolactone chains that deviate from the predetermined range to the larger side. That is, although the caprolactone chain varies depending on R ₁ , it is, for example, 8
When it becomes larger, it becomes easier to crystallize in a stressed state, especially in a state of being stored at a low temperature.
This is because the portion 8 is also easily crystallized. This low temperature crystallization has serious defects in functions such as viscoelasticity and high friction coefficient as an elastomer, and has a drawback that use environment and storage environment are significantly limited.

On the other hand, when the caprolactone chain is small, Tg increases and the temperature range in which it can be used as an elastomer is limited. In the present invention, Tg is defined as -20 ° C or lower. This range varies depending on the kind of R _{1 in} the above formula, and when R ₁ is derived from, for example, an aliphatic short-chain diol, it is not preferable that the number of chains is 2 or less, and R ₁ is, for example, an aromatic ring or an aliphatic ring. When it is derived from a short chain diol containing a cyclic structure such as a ring, it is not preferable that the number of chains is 3 or less, but R ₁
When is derived from a polymer, depending on the Tg of the polymer, there are cases where 2 or 1 chains are possible.

By the way, for example, Japanese Patent Application Laid-Open No. 2-628 discloses a lactone polymer having a narrow molecular weight distribution, and suggests that it is useful as a urethane raw material. However, such a conventional technique aims at reducing the viscosity of the lactone polymer and improving its handleability, and does not suggest the technique of the present invention. Also, it is needless to say that the description that it is useful as a urethane raw material means that it is used as a raw material of cast polyurethane or thermoplastic polyurethane from the state of the art. That is, as a polyol raw material for a cast or thermoplastic polyurethane consisting of a hard segment consisting of an isocyanate and a chain extender, and a polyol soft segment, it is considered that a highly crystalline raw material such as ε-caprolactone polymer can also be used. However, as the polyol raw material of the kneading type polyurethane composed of the soft segment and the isocyanate bond, a highly crystalline one cannot be used, and only a polyol having a reduced crystallinity by introducing a branched chain or a copolymerization component is used. It has been considered possible. Therefore, for a person skilled in the art, a means for embodying the idea of using a highly crystalline lactone polymer as a raw material for a kneading type polyurethane at a practical level has not been created, and it has been conventionally used as a polyol raw material for a kneading type polyurethane. Was a very limited polyol such as ethylene propylene glycol adipate or ethylene butylene adipate.

The present invention completely overcomes the conventional technical common knowledge, and as described above, in the present invention, by adjusting the number of chains of the caprolactone chain portion, poly-ε having originally high crystallinity is obtained. The present invention is to obtain a kneading-type polyurethane having elasticity and preventing crystallization of a chain portion of a caprolactone-based polyol by the influence of an isocyanate unit constituting a urethane bond and R _{1 of the} above formula.

In the present invention, the polymerization initiator that forms a poly-ε-caprolactone diol, that is, the compound from which R ₁ is formed, has active hydrogen and forms a diol after ring-opening polymerization. Is.

The initiator may be one having a molecular weight distribution to some extent, that is, a long chain initiator, and examples of such a long chain initiator include a polycarbonate diol such as poly (1,6-hexamethylene carbonate) diol;
Poly (oxytetramethylene) glycol (PTMG)
And polyether diols such as polybutylene adipate diol and the like.

In the present invention, as the main component of the polyol,
The above-mentioned specific poly-ε-caprolactone-based diol, which is a long-chain polyol, is used, but in addition to this, generally used long-chain polyols and chain extenders can be used. As the generally used long-chain polyol, either a polyester-based polyol or a polyether-based polyol may be used, and a blend-copolymerized or partially modified one thereof may be used. Further, as the chain extender, for example, ethylene glycol,
A straight chain glycol having 2 to 12 main chain elements such as thiodiethanol, propylene glycol and butylene glycol; a diol having a side chain of 12 or less carbon atoms such as neopentyl glycol and 3-methyl-1,5-pentanediol. And diols having an unsaturated group having 12 or less carbon atoms such as 3-allyloxy-1,2-propanediol; and aromatic rings such as 1,4-bis (hydroxyethoxy) benzene and paraxylene glycol Examples thereof include diols having 12 or less carbon atoms and hydrogenated products thereof, and additionally, triols such as trimethylol, stearyl alcohol, hydroxyethyl acrylate and the like can be additionally used. In order to exert the effect of the present invention remarkably, the ratio of the ε-caprolactone unit contained in the above-mentioned specific poly-ε-caprolactone diol is 30% by weight or more based on the total polyol, and more preferably. ,
It is preferably 50% by weight or more.

As the polyisocyanate for reacting with such a polyol to form the polyurethane of the present invention, 2,6-toluene diisocyanate (TD) is used.
I), 4,4'-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPD
I), 1,5-naphthalene diisocyanate (ND
I), 3,3-dimethyldiphenyl-4,4'-diisocyanate (TODI) and the like can be mentioned. Especially 4,4'-diphenylmethane diisocyanate (MD
It is preferable to use a polyisocyanate containing I) because it is known to act as a crosslinking point of peroxide crosslinking.

The mixing ratio of the polyol and the polyisocyanate may be a general one. For example, the active hydrogen such as the hydroxyl group of the diol and the isocyanate group are mixed so as to be almost equimolar. For example, OHv (hydroxyl value: KH
Omg / g) 112, 25 parts by weight of MDI per 100 parts by weight of diol, and OHv 94, 20.8 parts by weight of MDI per 100 parts by weight of diol, OHv.
In case of 75, 1 MDI is added to 100 parts by weight of diol.
6.7 parts by weight.

In the kneading type polyurethane of the present invention, a curing agent is kneaded and thermoset (crosslinked). Examples of such a curing agent include organic peroxides for general synthetic rubbers, sulfur, organic sulfur-containing compounds, and isocyanates. Here, an organic peroxide is generally used, and examples of the organic peroxide include dicumyl peroxide and α, α′-bis (t-butylperoxyisopropyl) benzene. The amount of the organic peroxide compounded is 0.5 to 10 parts by weight, preferably about 1.5 to 5 parts by weight, based on 100 parts by weight of the total of the polyol and the isocyanate. Further, sulfur, it is possible to use an organic sulfur-containing compound as a curing agent, when the above-mentioned polymerization initiator or chain extender has an unsaturated bond, for example,
This is the case for 3-allyl-1,2-propanediol.
Here, as the organic sulfur-containing compound, a thiuram-based vulcanization accelerator such as TMTD (tetramethylthiuram disulfide), TETD (tetraethylthiuram disulfide), DPTT (dipentamethylenethiuram tetrasulfide), 4,4′-dithiomorpholine And so on.

When kneading and curing in this way,
Commonly used additives, that is, carbon black, reinforcing agents such as silica, anti-sticking agents such as wax,
A plasticizer such as dioctyl phthalate (DOP) can be used.

In the polyurethane of the present invention, a hydrolysis inhibitor such as polycarbodiimide may be used in an amount of about 0.2 to 3% by weight based on 100 parts by weight of the polyurethane as usual. The hydrolysis resistance of the polyurethane member of the present invention is about double or more than that of the conventional thermosetting kneading type polyurethane. Although the hydrolyzability is improved, the addition amount can be reduced to about 20% to 50% in order to achieve the same level of hydrolyzability as the conventional one. Since hydrolysis inhibitors are generally expensive, they can greatly contribute to cost reduction.

The reaction conditions of the kneading type polyurethane are generally 70 ° C. to 150 ° C. for 10 to 120 minutes, and then generally aged at 60 ° C. to 120 ° C. for about 6 to 48 hours. To do. Further, the thermosetting condition is determined by the decomposition characteristics of the organic peroxide used when an organic peroxide is used as a curing agent, but is usually 3 to 6 at 150 to 180 ° C.
It is preferable to set the condition of 0 minutes.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to embodiments.

(Reference Example) Prior to the examples, 118 parts by weight of 1,6-hexanediol was used as an initiator, 912 parts by weight of ε-caprolactone was used, and 30 ppm of catalyst (SnCl ₂ ) was used.
When poly (ε-caprolactone-based diol) was produced by reacting in the presence of 130 ° C. until the residual monomer was less than 1%, the obtained poly-ε-caprolactone had a molecular weight of 1020 and Mw / Mn = 1.2, the average number of chains was 4.0, and the distribution of caprolactone chains was 1.2.
It was estimated to be the degree. Therefore, this production condition was used as the production condition of poly-ε-caprolactone having a small molecular weight distribution, and the following examples were carried out.

Further, MD is added to 100 parts by weight of this polyol.
I (4,4'-diphenylmethane diisocyanate) 2
4.5 parts by weight was added, and the mixture was reacted at 100 ° C. for 4 hours to obtain millable urethane. Furthermore, this millable urethane 1
5 parts by weight of peroxide cross-linking agent Perkmill D-40 (trade name; manufactured by NOF CORPORATION) was mixed with 00 parts by weight with a roll,
Molding was performed by molding at 160 ° C. for 20 minutes with a press.

(Examples) 510 parts by weight of 1,6-hexanecarbonate-based polyol CD205 (trade name; manufactured by Daicel Chemical Industries, Ltd.) was used as an initiator, and poly-ε-caprolactone-based was used under the same conditions as in Reference Example. A diol was produced to obtain a poly-ε-caprolactone diol having a molecular weight of 1400. Since CD205 has a molecular weight of 510, the average number of chains of caprolactone defined in the present invention is 4.0, and the distribution of caprolactone chains is estimated to be about 1.2 from the reference example.

Next, 100 parts by weight of this polyol is added to M
DI (4,4'-diphenylmethane diisocyanate)
17.8 parts by weight was added and reacted at 100 ° C. for 4 hours to obtain millable urethane.

Furthermore, 100 parts by weight of this millable urethane was mixed with 5 parts by weight of a peroxide cross-linking agent Perkmill D-40 (trade name; manufactured by NOF CORPORATION) with a roll, and the mixture was pressed at 160 ° C. for 20 minutes. Molding was performed to produce a molded product.

Comparative Example Sumipan 640S (trade name) manufactured by Sumitomo Bayer Urethane Co., Ltd. as a millable urethane
Was used to produce a molded product in the same manner as in the example.

(Measurement of Physical Properties) Using the molded articles of Examples, Reference Examples and Comparative Examples, the hardness and the hardness were measured according to JIS K6301.
Impact resilience, breaking strength, breaking elongation, and permanent compression strain,
Moreover, the glass transition point was measured based on JIS K7121. The results are shown in Table 1.

[0042]

[Table 1]

(Hydrolysis Test) Using the molded articles of each Example and Comparative Example, changes in hardness (JIS A) when left in water at 85 ° C. were measured. The result is shown in FIG.

From the results shown in FIG. 1, the molded products of the examples using the millable urethane of the present invention are very excellent in both strength and hydrolysis resistance as compared with the molded products using the conventional millable urethane. I found out that

[0045]

As described above, the polyurethane of the present invention is a kneading type polyurethane that can be produced by using conventional general rubber processing equipment. However, the polyurethane containing the poly-ε-caprolactone diol as a main component is By using a specific polyol in which the average value of ε-caprolactone chain in the caprolactone-based diol is within a predetermined range and the molecular weight distribution Mw / Mn of the poly-ε-caprolactone-based diol is 1.0 to 1.5, It is possible to exhibit outstanding mechanical strength and to significantly improve hydrolysis resistance without causing crystallization even at low temperatures.

[Brief description of drawings]

FIG. 1 is a view showing a result of a hydrolyzability test of the present invention.

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Claims (8)

(57) [Claims] 1. A kneading polyurethane resulting from the reaction of polyol and polyisocyanate, the kneaded poly
Kneading type polyurethane containing a curing agent for crosslinking urethane
A composition, wherein the polyol is a polycarbonate diol, a polyester
Selected from ether diol and polyester diol
At least one polymerization initiator R ₁ (OH) ₂ and ε-cap
Reacting the Rorakuton a main component poly -ε- caprolactone based diol represented by the following formula (I) obtained, and an average is produced caprolactone chain to the formulation molecular weight distribution of the ε- caprolactone chain portion is narrowed value
Controlled to 8 or less, the poly-ε-caprolactone-based di-
Molecular weight distribution Mw / M of all caprolactone chain
n is 1.0 to 1.5 and includes the urethane bond.
Due to the influence of the cyanate unit and the above R ₁ ,
A kneading-type polyurethane composition characterized in that the crystallinity of a prolactone chain is inhibited . [Chemical 1] (Here, [] indicates a caprolactone chain portion, and m
And n represent the number of chains, and R ₁ is a polymerization initiator R ₁ (O
H) ₂ and R ₁ (OH) ₂ has a molecular weight distribution) 2. The kneading-type polyurethane composition according to claim 1, wherein the curing agent is at least one selected from organic peroxides, sulfur, organic sulfur-containing compounds and isocyanate compounds . 3. The poly-ε according to claim 1 or 2.
-Caprolactone-based diol is SnCl ₂ and the following formula
Using a catalyst selected from the tin catalysts represented by (II) 1
A kneading type polyurethane composition, which is produced under a reaction condition of 50 ° C. or lower. [Chemical 2] (Here, R ₂ represents hydrogen, an alkyl group or an aryl group, X represents a hydroxyl group, an alkoxide group, or a halogen other than fluorine) 4. The kneading type polyurethane composition according to claim 1, wherein the average value of the caprolactone chain is controlled in the range of 3 to 8. 5. The polyisocyanate according to claim 1 , wherein the polyisocyanate is 2,6-toluene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1, 5-naphthalene diisocyanate (NDI) and 3,3-dimethyldiphenyl-4,4 '
A kneading type polyurethane composition characterized by being at least one selected from diisocyanates (TODI)
Thing . 6. The content ratio of ε-caprolactone unit in all polyols according to claim 1 , which is 30.
Kneading-type polyurethane characterized by being more than weight%
Composition . 7. The kneading-type polyurethane composition according to claim 1 , wherein the kneading-type polyurethane has a glass transition temperature Tg of −20 ° C. or lower. 8. A polyurethane molded product obtained by crosslinking and molding the kneading-type polyurethane composition according to claim 1 .