A POLYURETHANE FOAM AND A POLYURETHANE COMPOSITE COMPRISING THE SAME

Abstract

The present invention relates to an isocyanate reactive component comprising a specific polyol mixture useful for the preparation of homogenous reactive polyurethane compositions. The invention further relates to a reactive polyurethane composition comprising such isocyanate reactive component and an isocyanate component. It also relates to a homogeneous polyurethane foam having good mold release property and surface quality prepared from such reactive polyurethane compositions. In a further aspect, it relates to a polyurethane composite comprising such homogenous polyurethane foam and having good and flat surface appearance after processing.

Claims

1. An isocyanate reactive component B) comprising a polyether polyol composition, the polyether polyol composition comprising: b1) a first polyether polyol, having a functionality of 1.6-2.4, a hydroxyl value of 60-140 mg KOH/g, in an amount of 30-40 mol-%, based on the theoretically calculated total mole number of the polyether polyol composition, b2) a second polyether polyol, having a functionality of 7.6-8.4, a hydroxyl value of 480-560 mg KOH/g, in an amount of 35-55 mol-%, based on the theoretically calculated total mole number of the polyether polyol composition, and b3) a third polyether polyol, selected from polyether polyols derived from diphenylmethane diamine and/or toluenediamine, having a functionality of 3.6-4.4, and a hydroxyl value of 290-370 mg KOH/g, in an amount of 13-27 mol-%, mol-% based on the theoretically calculated total mole number of the polyether polyol composition.

2. The isocyanate reactive component according to claim 1, wherein the second polyether polyol is selected from the group consisting of polyether polyols derived from saccharose.

3. The isocyanate reactive component according to claim 1, wherein all of the first polyether polyol, second polyether polyol, and third polyether polyol are selected from the group consisting of propylene oxide-based polyether polyols.

4. The isocyanate reactive component according to claim 1, further comprising a foaming agent comprising at least one of dichlorofluoroethane, cyclopentane, pentafluorobutane, pentafluoropropane, trifluorochloropropylene, and hexafluorobutene.

5. The isocyanate reactive component according to claim 4, wherein the foaming agent additionally includes water.

6. A reactive polyurethane composition useful for the production of polyurethane foams with good and flat surface appearance, comprising: an isocyanate component A), the isocyanate component comprising one or more polyisocyanate(s); an isocyanate reactive component B) according to claim 1; and a foaming agent C).

7. A polyurethane foam obtained by reaction of the reactive polyurethane composition according to claim 6.

8. The polyurethane foam according to claim 7, wherein the core density of the polyurethane foam is 35-70 kg/m3.

9. The polyurethane foam according to claim 7, wherein the closed cell proportion of the polyurethane foam is 85-98%.

10. A discontinuous process for the production of a polyurethane composite comprising a shell and a polyurethane foam therein, comprising the steps: i) providing a shell in a mold ii) closing the mold iii) injecting the reactive polyurethane composition according to claim 6 in the shell in the mold iv) foaming the reactive polyurethane composition v) releasing the resulting polyurethane composite comprising the shell and the polyurethane foam from the mold.

11. The polyurethane composite prepared by the discontinuous process according to claim 10.

12. The polyurethane composite prepared by a discontinuous process according to claim 10, wherein the shell has a plate-like or hollow cylindrical shape.

13. A method of using the polyurethane composite prepared by the discontinuous process according to claim 10, wherein the polyurethane composite is selected from roof panels, side panels, bottom panels, or door panels of a container; roof panels, side panels, or bottom panels, or door panels of a prefabricated house; roof panels, side panels, or bottom panels, or door panels of a refrigerator house; insulation panels of an air-conditioner; and insulation pipelines.

Description

EXAMPLES

[0047] The invention is further described as below in combination with specific examples. It is to be understood by those skilled in the art, however, that these examples are merely illustrative of the present invention and are not construed to be restrictive of the scope of the invention.

[0048] The commercially available raw materials used in the examples are shown below:

[0049] Polyol 1: a propylene oxide-based polyether polyol with propylene glycol as the initiator, having a functionality of 2 and a hydroxyl value of 100 mg KOH/g;

[0050] Polyol 2: a propylene oxide-based polyether polyol with saccharose as the initiator, having a functionality of 8 and a hydroxyl value of 525 mg KOH/g;

[0051] Polyol 3: a propylene oxide-based polyether polyol with o-TDA as the initiator, having a functionality of 4 and a hydroxyl value of 345 mg KOH/g;

[0052] Yoke TCPP: Tris(2-chloroisopropyl) phosphate, a flame retardant, purchased from Jiangsu Yoke Technology Co., Ltd.;

[0053] Niax L6920: a foam stabilizer, purchased from Momentive Performance Materials (China) Co., Ltd.;

[0054] Dabco Polycat 41: a polyurethane synthesis catalyst, purchased from Air Products and Chemicals (China) Co., Ltd.;

[0055] Dabco Polycat PC8: a polyurethane synthesis catalyst, purchased from Air Products and Chemicals (China) Co., Ltd.;

[0056] Desmodur 44V20L: polymeric MDI, having an NCO content of 31.5 wt. %, purchased from Covestro Polymers (China) Co., Ltd.

[0057] Preparation of Polyurethane Composites

[0058] The prefabricated hollow shell part (panel shape) was placed in the mold and the mold was closed. The hollow shell member was preheated in the mold until the surface temperature of its surface material reached 30-45 C.

[0059] The components in Table 1 (total quantity: 80 kg) except for the isocyanate and physical blowing agent component were mixed under stirring to obtain an isocyanate reactive mixture.

[0060] Thereafter, the isocyanate reactive mixture and the isocyanate component were introduced and mixed in the mixing head of the high-pressure foaming machine (the mixing head was at a pressure of 100 to 160 bar).

[0061] The polyurethane reactive mixture was then injected into the prefabricated hollow shell part in the mold through the mixing head, foamed and expanded in the hollow shell until the hollow shell was fully filled. After the foaming reaction was completed, the foamed article was removed from the mold and the polyurethane composite was obtained.

[0062] Compatibility Testing Method

[0063] Cyclopentane and combined polyether stock (i.e., all components listed in Table 1 except for the isocyanate and cyclopentane) were mixed thoroughly, wherein the mixing weight ratio of cyclopentane to the combined polyether was 12:100, 15:100, 18:100 and 21:100. After well mixed, the solution was sealed with the transparent tube and left to stand at room temperature (20 C.) for 72 hours to be observed. If the solution within the tube shows clarity, it reveals an excellent compatibility; if the solution within the tube shows slight turbidity, it reveals a good compatibility; whereas, if the solution within the tube shows severe turbidity, two-phase or multi-phase separation, it reveals a poor compatibility. The testing results in Table 1 show that the compatibility of the formulations 1, 2 and 3 was poor, good and excellent, respectively.

TABLE-US-00001 TABLE 1 Formulations of the polyurethane foam and the compatibility thereof Formulations 1 (Comparative) 2 3 (Comparative) Example 1 2 3 4 5 6 7 8 9 10 11 12 Polyol 1, mol-%.sup.1 45 35 25 Polyol 2, mol-%.sup.1 45 45 45 Polyol 3, mol-%.sup.1 10 20 30 Yoke TCPP, pbw 10 10 10 10 10 10 10 10 10 10 10 10 Niax L6920, pbw 2 2 2 2 2 2 2 2 2 2 2 2 Dabco Polycat PC8, 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 pbw Dabco Polycat 41, pbw 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Water, wt-%.sup.2 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Polyol masterbatch, 100 100 100 100 100 100 100 100 100 100 100 100 pbw Cyclopentane, pbw 12 15 18 21 12 15 18 21 12 15 18 21 Isocyanate, pbw 118 118 118 118 118 118 118 118 118 118 118 118 Compatibility test Clear Clear Turbid delamination Clear Clear Clear Slightly Clear Clear Clear Clear turbid Compatibility grading Poor Good Excellent .sup.1mol-% based on the theoretically calculated total mole number of the polyether polyol composition (polyols 1-3) .sup.2wt.-% in relation to the polyurethane reactive composition

[0064] Testing Method for Mold Release Performance

[0065] A mold of 300300100 mm was used with the mold temperature controlled at 40 C. and the overall foam density of the mold was 55 kg/m.sup.3. The components in Table 2 (total quantity=495 g) were mixed and then disposed into a carton box placed in the mold. The mold was firmly closed. The foaming reaction took place in the mold. After 20 minutes starting from the mixing of the components, the mold was opened and the foamed molding product was taken out. The maximum expansion height at the center of the foamed molding product was measured. The larger the expansion height is, the worse the mold release performance is. Generally, an expansion height of 1.0-3.5 mm reveals a good mold release performance. The testing results are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Tests for the mold release property Comp. Ex. 1 Ex. 5 Comp. Ex. 9 Expansion height (mm) 4.5 2.6 1.8

[0066] Surface Bubble Test

[0067] An L-shaped mold was used with the mold temperature controlled at 40 C. and the inner surface of the mold was evenly coated with a mold release agent. The overall foam density of the mold was 55 kg/m.sup.3. The formulations in Table 1 were mixed and then disposed into the mold. The mold was closed and the foaming reaction took place in the mold. After 30 minutes starting from the mixing of the components, the mold was opened and the foamed molding product was taken out.

[0068] The bubbles on the surfaces of the L-shaped foams were analyzed as follows:

[0069] i. the depth of the bubble,

[0070] ii. the volume of the bubble and

[0071] iii. the total number of the bubbles.

[0072] The smaller these three values, the better is the overall surface bubble performance (surface quality). The surface qualities of the obtained polyurethane foams of Comparative Examples 1 and 9, and Example 5 are shown in FIG. 1. Table 3 demonstrates the results of the analysis of the surface qualities for the polyurethane foams. FIG. 1 shows a picture of the foams: On the left side is the foam of Comparative Example 9, the middle is the foam of Example 5, and the right side is the foam of Comparative Example 1.

TABLE-US-00003 TABLE 3 Surface bubble tests for the polyurethane foam Comp. Ex. 1 Ex. 5 Comp. Ex. 9 Surface bubble grading Excellent Good Poor

[0073] By comparing the compatibility, mold release property and surface property of the formulations above, it is found that only inventive formulation 2 achieves the advantageous balance between each of the properties.