JPH02170813A - Polyurethane-based molding material - Google Patents

Abstract

PURPOSE:To provide the title molding material excellent in resistance to oil, heat and cold and non-yellowingness, comprising an aliphatic diisocyanate, specific aliphatic copolycarbonate polyol and chain extender. CONSTITUTION:The objective molding material comprising (A) an aliphatic diisocyanate (e.g. 4,4'-methylenebiscyclohexyl diisocyanate), (B) an aliphatic copolycarbonate polyol consisting of respective recurring units of formulas I and II with the ratio: formula I/formula II= (9:1)-(1:9), and (C) a chain extender having two active hydrogens reactive with isocyanate (e.g. water, low-molecular weight diol, low-molecular weight diamine).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a polyurethane molding material that is excellent in oil resistance and heat resistance, particularly in cold resistance and non-yellowing. In recent years, thermoplastic polyurethane has been in increasing demand as a molding material as a resin that provides an elastomer with excellent toughness, oil resistance, and abrasion resistance.

(Prior art) - Most of the polyurethane molding materials currently on the market are molded products using yellowing type polyurethane, and in recent years, thermoplastic polyurethane has improved its toughness, oil resistance, and abrasion resistance. As properties such as these are highly valued and the market expands, the demand for non-yellowing is increasing. For example, in applications such as highly fashionable watch bands, products using conventional yellowing polyurethane are generally colored black to make the discoloration over time less noticeable. However, recently, products in various colors have become desired, and demand for non-yellowing polyurethane has increased.

In addition, the properties of polyurethane molding materials currently on the market largely depend on the high molecular weight polyol used as the polyurethane raw material.
According to page 139 (published by CMC), when polyester polyol is used, water resistance is poor, but mechanical strength and heat resistance are relatively good. On the other hand, when polyether polyol is used, water resistance is improved, but heat resistance and mechanical strength are inferior. Poly-ε-caprolactone polyol has excellent mechanical properties, heat resistance, and cold resistance, but is poor in water resistance.

Aliphatic polycarbonate polyols have excellent water resistance, mechanical properties, and heat resistance, but are poor in cold resistance. This is how it goes. Therefore, if the cold resistance of polyurethane using an aliphatic polycarbonate polyol is improved, we can expect a polyurethane molding material that is non-yellowing, has excellent cold resistance, and has well-balanced other physical properties compared to currently commercially available products.

(Problems to be Solved by the Invention) An object of the present invention is to provide a polyurethane-based molding material that is excellent in heat resistance and oil resistance, particularly non-yellowing and cold resistance.

(Means for Solving the Problems) As a result of extensive research, the present inventors have found that, as aliphatic copolycarbonate polyols, the repeating units are (A) -E-0 -CH OC10 and (B) A polyurethane molding material comprising an aliphatic copolycarbonate diol, an aliphatic diisocyanate, and a chain extender in which the ratio of A and B is 9:1 to 1:9, While cold resistance is significantly improved compared to conventional polyurethane molding materials using aliphatic polycarbonate polyols, other physical properties not only maintain the excellent properties of conventional products, but also allow for predictable total heat. Compression set will improve! Ii iE, it was discovered that an ideal polyurethane molding material currently desired in the market could be obtained, and the present invention was completed.

That is, the present invention provides a polyurethane comprising an aliphatic diisocyanate, an aliphatic copolycarbonate polyol, and a chain extender having two active hydrogens capable of reacting with the isocyanate, in which the aliphatic copolycarbonate polyol is
As a repeating unit, it consists of (A) 廿O廿CH斤oC士(B) 廿0,000-CH 5Oc-ner,
It is a polyurethane molding material in which the ratio of B and B is 9=1 to 1:9.

The present invention will be explained below.

The aliphatic copolycarbonate polyol used in the present invention is described by Shell, Polymer Review (Pol.
ymer Reuiew) Volume 9, pp. 9-20 (196
It is synthesized from 1,6-hexanediol and 1,5-bentanediol by various methods described in 4). In addition, the molecular weight is 500 to 10,000, and the repeating units in the polymer are (A) -(-OfCH OC and (B) tO+ CH OC, and the ratio of A and B is 91 to 1:9. If the ratio of A and B is outside this range, the aliphatic copolycarbonate polyol will become crystalline and the cold resistance will not be improved.

The aliphatic diisocyanate used in the present invention includes:
4.4'-methylenebiscyclohexyl diisocyanate (hydrogenated MD[), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPD)
I), cyclohexane diisocyanate (hydrogenated XDT)
Examples include known aliphatic diisocyanates such as.

Chain extenders used in the present invention include those commonly used in the polyurethane industry.

“Recent Polyurethane Application Technology” (CMCl) supervised by Keiji Iwata
985), pages 25 to 27 of the known water and low molecule ■
Includes diols, low molecular weight diamines, etc.

Along with the aliphatic copolycarbonate polyol used in the present invention, a known high molecular weight polyol may be used in combination, depending on the use of the polyurethane, within a range that does not impair the effects of the present invention. Known high molecular weight polyols include ``Polyurethane Foam'' by Yoshio Imai (Kobunshi Kankakai 1).
Examples include the known polyester polyols, polyether polyols, polycarbonate polyols, etc. described on pages 12 to 23 of 1987).

As a method for producing polyurethane, a urethanization reaction technique known in the polyurethane industry is used. For example, high molecular weight polyol and organic diisocyanate are mixed at room temperature to
A prepolymer method in which an NGO-terminated urethane prepolymer is synthesized by reacting at 200°C, a chain extender is added to this, and the molecular weight is increased at room temperature to 200°C to obtain the desired thermoplastic polyurethane. Alternatively, there is a one-shot method in which the high molecular weight polyol, an organic diisocyanate, and a chain extender are added all at once and reacted at room temperature to 200°C to obtain the desired thermoplastic polyurethane. Urethane used in the molding material of the present invention can also be produced by these methods. In these reactions, it is of course possible to use a known polymerization catalyst in the urethanization reaction, such as an appropriate amount of a tertiary amine or an organic metal salt of tin or titanium, if necessary. Examples include various polymerization catalysts described in "Polyurethane Technology" by Keiji Iwata (published by Nikkan Kogyo Shimbun), pages 23-32.These reactions may also be carried out using a solvent, and preferred solvents include is dimethylformamide, diethylformamide, dimethylsulfoxide,
Examples include one or more of dimethylacetamide, tetrahydrofuran, methyl isobutyl ketone, dioxane, cyclohexanone, benzene, and toluene.

Furthermore, various additives can be used to improve the heat resistance, light resistance, mold release properties, etc. of the polyurethane.

For example, phenolic antioxidants, amine antioxidants, sulfur antioxidants, and phosphoric acid described in Yoshinaga Abe and Makoto Sudo, New Edition Plastic Compounding Agents (Taiseisha) No. 151-158. -based antioxidants or benzophenone-based, salicylate-based, benzotriazole-based, metal salt-based, hindered amine-based ultraviolet absorbers described on pages 178 to 182 of the plastic compounding agent, further reinforcing fibers, fillers, colorants, Includes mold release agents, flame retardants, etc.

The polyurethane obtained can be molded by various commonly used methods such as injection molding, extrusion molding, calendar processing, blow molding, and solution processing.

(Example) Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples at all.

The physical properties of the polyurethane molding materials in Examples were evaluated by the following method.

Conforms to JIS-6301.

JI sample (width 20mm, length 50mm, thickness 2mm)
After immersion in S Noa oil at 70°C for 8 hours, the degree of swelling was determined using the following formula.

Wl: Air quality MCg before immersion) W: Mass in air after immersion (g) Salmon 11: According to JIS4-6301.

Using a sample (width 3 mm, length 38 cylinders, thickness 2 mm),
The modulus at low temperature is measured using a Gehman torsion tester, and the ratio to the torsional modulus measured at 23±3°C is determined using the following formula.

RM: specific modulus θ. : Twisting angle θl of the test piece at 23±3'C: T2, T5, T, the temperature at which the torsion angle RM of the test piece at low temperature is 2.5.10.

Expressed as

11: Measure the molecular weight of the resin before and after injection molding using GPC, and use the molecular weight retention rate as a measure of thermal stability.

■Viewing ratio: According to JIS-7103.

After irradiating a sample (length: 40 squares, width: 40 mm, thickness: 2 bars) for 400 hours using a QUV tester, the degree of yellowness is measured using a colorimeter, and the degree of yellowing is determined using the following formula.

ΔY　I　=Y　r−Y　I.

ΔYI: Yellowing index YI: Yellowing index YI after exposure. : Initial yellowness of test sample or test piece (synthesis of aliphatic copolycarbonate polyol) Synthesis Example 1 1.6 in a reactor equipped with a stirrer, a thermometer, and a fractionating tube.
- 472 parts (4.0 mol) of hexanediol and 1,
Add 416 parts (4.0 mol) of 5-bentanediol,
1.84 parts of metallic sodium (0,08
mol) was added under stirring. After complete reaction of the sodium, 472 parts (8.0 mol) of diethyl carbonate were introduced. When the reaction temperature was raised to 95-100°C, ethanol began to distill out.

The temperature was gradually increased to 160°C in about 6 hours.

During this time, ethanol containing about 10% diethyl carbonate was distilled out. After that, the pressure of the reactor was further increased to 10110
The reaction volume was adjusted to 1l1 or less, and the reaction was carried out at 200°C for 4 hours with strong stirring. After cooling, the generated polymer was dissolved in dichloromethane, neutralized with dilute acid, washed with water several times, dehydrated with anhydrous sodium sulfate, the solvent was removed by distillation, and further heated at 2 to 3 mm Hg, 140 °C. Let it dry for several hours. The molecular weight of the obtained aliphatic copolycarbonate polyol was 2,000. This polycarbonate polyol is abbreviated as PC-A.

Synthesis Examples 2 to 7 1,6-hexanediol and 1.5 as diols
- except that the amounts of bentanediol shown in Table 1 are used;
Aliphatic copolycarbonate polyol BG (PC-4-PC-G) was obtained in the same manner as in Synthesis Example 1. The molecular weight of each is shown in Table 1.

Example 1 200 parts of PC-A obtained in Synthesis Example 1 and 100.8 parts of hexamethylene diisocyanate were charged into a reactor equipped with a stirrer, a thermometer, and a cooling tube, and reacted at 100°C for 4 hours to react with N.
A CO-terminated prepolymer was obtained. To the prepolymer were added 43.44 parts of 1,4-butanediol as a chain extender, 0.52 parts of n-butanol as a terminal stopper, and 0.007 parts of diptyltin dilaurate as a catalyst. After reacting at 170° C. for 2 hours using an extruder [KR-35 type universal extruder for LABO, manufactured by Kasamatsu Chemical Research Institute], the mixture was formed into strands using a screw type extruder, and then passed through a pelletizer to produce pellets. The molecular weight of the obtained polyurethane pellets was 48,000 C (using GPC-) ILc-802A manufactured by Toso Corporation). The polyurethane pellets were injection molded using an injection molding machine, and
A sheet with 0 cylinder, 110+ nm width, and 2 threshold thickness was obtained (injection temperature 200'C). Oil resistance, heat resistance, cold resistance, and light resistance were measured using samples for physical property evaluation prepared from the sheet. The results are shown in Table 2.

Examples 2 to 5 Using the PC-C-PC-F obtained in Synthesis Examples 3 to 6, polyurethane C-F was obtained in the same manner as in Example 1, and after making a strand, it was made into pellets with a length of 110 mm, a width of 110 mm, An injection molded sheet with a thickness of 2 mm was produced. Oil resistance, heat resistance, cold resistance, and light resistance were measured using samples for physical property evaluation prepared from the sheet. The results are shown in Table 2.

Comparative Example 1 Using PC-B obtained in Synthesis Example 2, polyurethane B was obtained in the same manner as in Example 1, and after strand production, it was made into a pellet, measuring 110 mm in length, 110 mm in width, and 2 u+m in thickness.
An injection molded sheet was produced. A sample for physical property evaluation was prepared using the sheet, and oil resistance, heat resistance, cold resistance, and light resistance were measured. The results are shown in Table 2.

Comparative Example 2 Using the PC-G obtained in Synthesis Example 7, polyurethane G was obtained in the same manner as in Example 1, and after strand production, it was pelletized to produce an injection molded sheet with a length of 110 mm, a width of 110 mm, and a thickness of 2 mm. A sample for physical property evaluation was prepared using the sheet, and oil resistance, heat resistance, cold resistance, and light resistance were measured. The results are shown in Table 2.

Comparative Example 3 Polyurethane H was obtained in the same molar ratio as in Comparative Example 1 except that hexamethylene diisocyanate was changed to 4,4'-diphenylmethane diisocyanate, and after strand production, it was pelletized, and the length was 110 mm, the width was 110 + nn,
An injection molded sheet with a thickness of 2 mm was produced. A sample for physical property evaluation was prepared using the sheet, and oil resistance, heat resistance, cold resistance, and light resistance were measured.

The results are shown in Table 2.

Comparative Example 4 In Comparative Example 3, the aliphatic copolycarbonate polyol was replaced with polycaprolactone polyol (manufactured by Daicel Chemical Co., Ltd.).
Polyurethane (2) was obtained in the same manner except that it was changed to Plaxel 2201 (molecular weight 2,000), and after making strands, it was pelletized and had a width of 110 mm, a width of 110 mm, and a thickness of 2 m.
An injection molded sheet of m was produced.

A sample for physical property evaluation was prepared using the sheet, and oil resistance,
Heat resistance, cold resistance, and light resistance were measured. The results are shown in Table 2.

Comparative Example 5 Polyurethane J was obtained in the same molar ratio as in Example 1 except that hexamethylene diisocyanate was changed to 4,4゛-diphenylmethane diisocyanate, and after forming a strand, it was pelletized, and the length was 110 mm, the width was 110 mm, and the thickness was 110 mm. A 2 mm injection molded sheet was made, and samples for physical property evaluation were made using the sheet to evaluate oil resistance, heat resistance, cold resistance,
Light resistance was measured. The results are shown in Table 2.

The following margin Table 1 Table 2 The following margin (effect of the invention) The repeating unit of the present invention consists of (A) 1,000 - 0 ÷ - 〇H Tsuji = OC - ÷ - and the ratio of A and B is 9:1 ~ A polyurethane molding material composed of an aliphatic copolycarbonate polyol, an aliphatic diisocyanate, and a chain extender in a ratio of 1:9 has excellent oil resistance, heat resistance, cold resistance, and non-yellowing properties.

Claims (1)

[Claims] An aliphatic diisocyanate, an aliphatic copolycarbonate polyol, and two active hydrogens capable of reacting with the isocyanate.
In polyurethane consisting of a chain extender, an aliphatic copolycarbonate polyol is used as a repeating unit. A polyurethane molding material in which the ratio of A and B is 9:1 to 1:9.