JP3121415B2 - Thermoplastic polyurethane composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a composition comprising a specific thermoplastic polyurethane and a compounding agent. The thermoplastic polyurethane composition of the present invention has excellent heat resistance and mold release properties, and is suitable for calendering for film production.

[0002]

2. Description of the Related Art Conventionally, thermoplastic polyurethane has attracted attention as an alternative material to rubber and plastics because it has a high elastic modulus and has many features such as excellent abrasion resistance and oil resistance. Many plastics processing methods are becoming applicable. But,
The calendering method is widely used as a method for producing films and sheets of various thicknesses from a thin film of rubber or vinyl chloride resin to a sheet having a thickness of several millimeters.

The calendering method is a method in which a resin is retained in a valley between high-temperature calender rolls to perform defoaming and kneading, and then rolled to a predetermined thickness in a gap between the rolls. When a thin film is produced by this method, it is necessary to increase the roll temperature to increase the fluidity of the resin and to narrow the gap between the rolls. However, the thermoplastic polyurethane has a high tackiness, and the releasability tends to be further deteriorated when the temperature is increased, so that a film having a uniform form cannot be released from the calender roll. Further, since calendering is performed by an open roll method, the resin is exposed to high temperature conditions in the air during the processing. Therefore, a polyurethane having insufficient heat resistance such as a polyether-based thermoplastic polyurethane is unsuitable for calendering because coloring and thermal decomposition occur.

[0004] As described above, thermoplastic polyurethane is generally not suitable as a material suitable for a calendering method because of its strong adhesiveness to a metal roll and poor heat resistance. For this reason, a new polyurethane-based material suitable for a calendering method has been demanded.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional thermoplastic polyurethane, that is, a heat-resistant polyurethane having excellent heat resistance and good mold release from a calender roll. An object of the present invention is to provide a plastic polyurethane composition.

[0006]

According to the present invention, the object of the present invention is to provide a polyester or polycarbonate chain having a number average molecular weight of 1,000 to 5,000 containing a low molecular weight diol unit having 6 to 9 carbon atoms as a soft segment in a molecule. The thermoplastic polyurethane composition comprises 100 parts by weight of a thermoplastic polyurethane and 0.3 to 3 parts by weight of a condensate of a higher fatty acid and an aliphatic polyol.

The polyester or polycarbonate chain constituting the soft segment in the molecule of the thermoplastic polyurethane used in the present invention contains a low molecular weight diol unit having 6 to 9 carbon atoms. Such low molecular diol units include
From the point that the releasability from the calender roll of the composition is good, and coloring and thermal decomposition during calendering are suppressed,
C6-9 carbon atoms such as 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,7-heptanediol, 2-methyl-1,8-octanediol and 1,9-nonanediol; 2 from the alkylene glycol molecule
A divalent group in which two hydrogen atoms in one hydroxyl group are removed is preferable, and in particular, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol or 1,9- From the molecule of nonanediol, two of the two hydroxyl groups
When the number of carbon atoms of the low molecular weight diol unit contained is 5 or less, adhesion of the composition to a roll during calendering, coloring and heat generation are preferred. Degradation is remarkable. From the viewpoint that the effects of the present invention are sufficiently exerted, the low-molecular diol unit having 6 to 9 carbon atoms may account for 50 mol% or more of all low-molecular diol units in the polyester and / or polycarbonate constituting the soft segment. preferable.

In the polyester chain constituting the soft segment, the low-molecular dicarboxylic acid unit contained together with the low-molecular diol unit includes a molecule of a saturated aliphatic dicarboxylic acid such as succinic acid, adipic acid, azelaic acid and sebacic acid. And a divalent group in a form in which two hydroxyl groups in two carboxyl groups are removed, and among them, a divalent group corresponding to adipic acid is preferable.

The number average molecular weight of the polyester or polycarbonate chain constituting the soft segment is 10
It is in the range of 00-5000. If it is less than 1000, the releasability of the composition from the calender roll is poor. On the other hand, when it exceeds 5,000, the melt viscosity of the thermoplastic polyurethane becomes high, and the calenderability becomes poor. From the point that calendar workability becomes particularly good, from 1500 to 30
It is preferably within the range of 00. A part of the soft segment in the molecule of the thermoplastic polyurethane used in the present invention may be a polyether chain such as polytetramethylene glycol, polypropylene glycol, or polyethylene glycol, but the effect of the present invention is sufficiently exhibited. In doing so, it is desirable that the ratio be limited to 40 mol% or less of the soft segment.

The thermoplastic polyurethane used in the present invention preferably has a nitrogen atom content in the range of 2.5 to 4.5% by weight. The nitrogen atom content is 2.
When the content is 5% by weight or more, the releasability from the calender roll is particularly good. When the content is 4.5% by weight or less, the melt viscosity of the composition becomes a value suitable for calendering. The logarithmic viscosity of the thermoplastic polyurethane used in the present invention is in the range of 0.95 to 1.5 dl / g, so that the sheet having good releasability from a calender roll and good mechanical performance can be obtained. Or it is preferable because a film can be obtained.

The thermoplastic polyurethane used in the present invention is, as a raw material for forming the desired soft segment, a polyester diol having a number average molecular weight of 1,000 to 5,000 containing a low molecular diol unit having 6 to 9 carbon atoms and / or Alternatively, it is produced by using a polycarbonate diol and, if desired, a small amount of another polymer polyol such as a polyether diol, and reacting this with a diisocyanate and a chain extender according to a conventional method. As a reaction method, a melt polymerization method is preferable. The diisocyanate to be used is an aliphatic, alicyclic or aromatic diisocyanate containing two isocyanate groups in a molecule, for example, 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate,
Examples include tolylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. As the diisocyanate, 4,4'-diphenylmethane diisocyanate is particularly preferred. As the chain extender, a chain growing agent known to be usable in the production of polyurethane, that is, a molecular weight of at least 2 containing at least two hydrogen atoms capable of reacting with isocyanate in the molecule.
00 or less low molecular weight compounds, for example, ethylene glycol, propylene glycol, 1,4-
Diols such as butanediol, neopentyl glycol, and 1,6-hexanediol are exemplified. As the chain extender, 1,4-butanediol is preferred. The number average molecular weight of the polyester diol and / or polycarbonate diol used can be determined from the hydroxyl value and the acid value according to a conventional method.

The condensate of a higher fatty acid and an aliphatic polyol used in the present invention will be described below. The “higher fatty acid” in the present invention is an aliphatic monobasic acid having 11 or more carbon atoms, which has a particularly high effect of improving the releasability from a calender roll and has good dispersibility in a thermoplastic polyurethane. From the viewpoint, straight-chain saturated fatty acids having 20 to 35 carbon atoms are preferred. A preferred example is montanic acid. Further, the "aliphatic polyol" in the present invention,
Aliphatic polyhydric alcohols having two or more hydroxyl groups in the molecule, preferred examples of which include ethylene glycol, propylene glycol, 1,4-butanediol,
C2-6 aliphatic polyhydric alcohols having 2-3 hydroxyl groups in the molecule, such as glycerin. The “condensate of a higher fatty acid and an aliphatic polyol” in the present invention is a compound in which substantially all of the hydroxyl groups of the aliphatic polyol are each esterified with a higher fatty acid. The condensate used in the present invention need not be a single compound, but may be any one or more compounds in the form of one or more aliphatic polyols esterified with one or more higher fatty acids. An example of such a condensate that is easily available is “Hoechst Wax E” manufactured by Hoechst Co. ), Hoechst “Hostalbu W
E4 "(a mixture of esterified products of a mixed higher fatty acid mainly composed of a linear saturated aliphatic carboxylic acid having 28 to 32 carbon atoms with glycerin) and the like.

The amount of the condensate is in the range of 0.3 to 3 parts by weight based on 100 parts by weight of the thermoplastic polyurethane. If the amount is less than 0.3 parts by weight, the composition tends to stick to the calender roll during processing. If it exceeds 3 parts by weight, the lubricity of the composition becomes excessive, and it becomes difficult to carry out plasticization by a calender roll.

The composition of the present invention may be prepared by mixing a predetermined amount of the condensate during the production of the above-mentioned thermoplastic polyurethane, or melt-kneading a predetermined amount of the above-mentioned condensate after the production of the thermoplastic polyurethane by using various extruders. It is manufactured by doing. At the time of mixing, additives such as a stabilizer, a lubricant, a filler, and a pigment can be added in such an amount that the effects of the present invention are not lost. By using an aliphatic amide such as ethylenebisstearic acid amide or methylenebisstearic acid amide as such a lubricant, the releasability from the roll may be further improved.

[0015]

The present invention will be described in detail with reference to the following examples. The nitrogen content of the thermoplastic polyurethane was determined by elemental analysis. The hardness of the thermoplastic polyurethane was measured according to JIS K7311.

Reference Example 1 (Production of polyester diol) 1600 g of a mixture of 2-methyl-1,8-octanediol and 1,9-nonanediol (molar ratio = 35: 65)
And 1460 g of adipic acid were charged into a reactor, and an esterification reaction was carried out at about 220 ° C. while distilling out generated water from the system while passing nitrogen gas into the system under normal pressure. When the acid value of the produced polyester became 0.3 or less, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. Since the polyester diol thus obtained (hereinafter referred to as polyester diol A) has a hydroxyl value of 56 and an acid value of 0.12, its number average molecular weight is 2,000.
It is.

Reference Example 2 (Production of Polyester Diol) In Reference Example 1, instead of the mixture of 2-methyl-1,8-octanediol and 1,9-nonanediol, the same molar number of 3-methyl-1,5- An esterification reaction was carried out in the same manner except that pentanediol was used, to obtain a polyester diol (hereinafter, referred to as polyester diol B).

Reference Examples 3 and 4 (Production of Polyester Diol) In Reference Example 1, 1,4 was replaced with a mixture of 2-methyl-1,8-octanediol and 1,9-nonanediol.
An esterification reaction was carried out in the same manner except that -butanediol was used to obtain two kinds of polyester diols (these are called polyester diols C and D).

Reference Example 5 (Production of polycarbonate diol) A mixture of 2-methyl-1,8-octanediol and 1,9-nonanediol (molar ratio = 35: 6) under a nitrogen stream.
5) 1730 g and diphenyl carbonate 2140
g was charged into a reactor and heated to 200 ° C. to evaporate the phenol produced out of the system. Temperature gradually 21
After raising the temperature to 0 to 220 ° C. and distilling out almost all of the generated phenol from the system, the pressure in the system was reduced to 6 to 10 mmHg, and the remaining phenol was completely distilled out of the system at the same temperature under the reduced pressure. Was. The polycarbonate diol thus obtained (hereinafter referred to as polycarbonate diol A) had a hydroxyl value of 56 and a number average molecular weight of 2,000.

For the polyester diols obtained in Reference Examples 1 to 4 and the polycarbonate diol obtained in Reference Example 5, the diol components and their compositions, the dicarboxylic acid components of the polyester diol, and the number average molecular weights are summarized in Table 1. .

[0021]

[Table 1]

In Table 1, the diol component and the dicarboxylic acid component are represented by the following abbreviations for diol and dicarboxylic acid, respectively. ND: 1,9-nonanediol MOD: 2-methyl-1,8-octanediol MPD: 3-methyl-1,5-pentanediol AD: adipic acid BD: 1,4-butanediol

Example 1 (Production of thermoplastic polyurethane composition and performance evaluation) A mixture of polyester diol A and 1,4-butanediol (hereinafter referred to as BD) at a molar ratio of 1: 2.6 was heated to 50 ° C. And 4,4'-diphenylmethane diisocyanate heated and melted at 50 ° C.
This is referred to as MDI).
The mixture was continuously charged into a twin-screw extruder rotating in a coaxial direction by a metering pump at a molar ratio of MDI to BD of 1: 3.6 to 2.6 to perform a continuous melt polymerization reaction. The resulting thermoplastic polyurethane melt was continuously extruded into water in the form of a strand, then cut with a pelletizer and formed into pellets.

To 100 parts by weight of the obtained polyurethane pellets, 1.0 part by weight of a condensate of a higher fatty acid and ethylene glycol (Hoechst wax E, manufactured by Hoechst) was added.
5mmφ twin screw extruder (cylinder temperature 1
The mixture was kneaded at a temperature of 70 to 210 ° C. and a die temperature of 190 ° C.) to form a pellet. Thus, pellets of the thermoplastic polyurethane composition were obtained.

Next, the obtained polyurethane composition pellets were mixed with a kneader (roll temperature: 1) comprising two metal rolls.
(75 ° C.). The time until the composition on the roll did not release from the roll was measured every 10 minutes. Table 2 shows the evaluation results.

Examples 2 and 3 (Production of thermoplastic polyurethane composition and evaluation of performance) The amount of Hoechst wax E was adjusted to 0.5 parts by weight or 2.0 parts by weight based on 100 parts by weight of thermoplastic polyurethane. Except for the above, pellets of the thermoplastic polyurethane composition were obtained in the same manner as in Example 1.

Using the thermoplastic polyurethane composition thus obtained, the same kneading test as in Example 1 was performed to evaluate the releasability. Table 2 shows the results.

Examples 4 and 5 (Production of thermoplastic polyurethane composition and evaluation of performance) In Example 1, polymer diol shown in Table 2 was used in place of polyester diol A, and polymer was used in a molar ratio shown in Table 2. Pellets of a thermoplastic polyurethane composition were obtained by carrying out the reaction and blending of Hoechst wax E in the same manner except that diol, MDI and BD were charged. Using these pellets, the releasability was evaluated in the same manner as in Example 1. Table 2 shows the obtained results.

Example 6 (Production and Evaluation of Performance of Thermoplastic Polyurethane Composition) Except for using Hoestub WE4 (manufactured by Hoechst, condensate of higher fatty acid and glycerin) in the same weight as Hoechst wax E, instead of Hoechst wax E In the same manner as in Example 1, pellets of the thermoplastic polyurethane composition were obtained. The releasability was evaluated in the same manner as in Example 1 using the pellets.
Table 2 shows the obtained results.

[0030]

[Table 2]

Comparative Example 1 (Evaluation of Performance of Thermoplastic Polyurethane) The thermoplastic polyurethane obtained in the same manner as in Example 1 was subjected to the same kneading test as in Example 1 without blending Hoechst wax E. did. Table 3 shows the obtained evaluation results.

Comparative Examples 2 and 3 (Production and Performance Evaluation of Thermoplastic Polyurethane Composition) In Example 1, polymer diols shown in Table 3 were used in place of polyester diol A, and polymers were prepared at molar ratios shown in Table 3. Pellets of a thermoplastic polyurethane composition were obtained by carrying out the reaction and blending of Hoechst wax E in the same manner except that diol, MDI and BD were charged. Using these pellets, the releasability was evaluated in the same manner as in Example 1. Table 3 shows the obtained results.

Comparative Examples 4 and 5 (Production and Evaluation of Performance of Thermoplastic Polyurethane Composition) The procedure of Example 1 was repeated except that the same weight of the lubricant shown in Table 3 was used instead of Hoechst wax E. A pellet of the plastic polyurethane composition was obtained. Using these pellets, the releasability was evaluated in the same manner as in Example 1. Table 3 shows the obtained results.

[0034]

[Table 3]

Comparative Example 6 (Production of Thermoplastic Polyurethane Composition and Performance Evaluation) To 100 parts by weight of pellets of a polyether-based thermoplastic polyurethane (Mobilon P-27 manufactured by Nisshinbo Industries, Inc.) were added 1.0 part by weight of Hoechst wax E. And a 35 mmφ twin-screw extruder (cylinder temperature 200 ° C., die temperature 190 ° C.), kneaded and added to form a pellet. When a kneading test similar to that of Example 1 was performed using this composition pellet, the releasability evaluation result was 30 minutes from the start of kneading to the start of adhesion.

Reference Example 6 (Production of sheet by calendering method) A thermoplastic polyurethane composition of the same kind as that obtained in each of Examples 1 to 6 was inverted L-type four-roll calender (roll temperature: 160 to 175 ° C). Into a sheet having a thickness of 1 mm. In any of the compositions, no sticking to the roll occurred, and the process passability was good for a long time. All of the obtained sheets had good morphology and no coloring was observed.

[0037]

As is clear from the above examples, the thermoplastic polyurethane composition provided by the present invention has a good releasability from a hot roll and a long processable time from the start of kneading to the start of sticking. . The composition of the present invention can effectively exhibit such performance in calendering, and by using the composition as a material, a thermoplastic polyurethane sheet or film can be stably produced for a long time by calendering. It becomes possible. Further, since the composition of the present invention is excellent in heat resistance, coloring of the obtained sheet or film is prevented.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-195117 (JP, A) JP-A-62-22817 (JP, A) JP-A-3-115417 (JP, A) JP-A-2- 265964 (JP, A) JP-A-50-108397 (JP, A) JP-A-63-202610 (JP, A) JP-A-63-238142 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 75/00-75/16 C08J 5/18 CFF CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. 100 parts by weight of a thermoplastic polyurethane containing, as a soft segment, a polyester or polycarbonate chain having a number average molecular weight of 1,000 to 5,000 containing a low molecular weight diol unit having 6 to 9 carbon atoms, a higher fatty acid and an aliphatic A thermoplastic polyurethane composition comprising 0.3 to 3 parts by weight of a condensate with a polyol.