阅读说明：本技术 使用单组分聚氨酯的注射成型方法 (Injection molding process using one-component polyurethane ) 是由 J-L·雷坎 A·斯科尔茨 G·纳波 M·布拉赫曼 于 2020-02-21 设计创作，主要内容包括：本发明涉及一种使用可热固化的单组分聚氨酯(PU)组合物通过低温和低压注射成型制备成型制品的方法,以及使用所述方法获得的成型制品。(The present invention relates to a method for preparing a molded article by low-temperature and low-pressure injection molding using a heat-curable one-component Polyurethane (PU) composition, and a molded article obtained using the method.)

1. A process for preparing a shaped article comprising:

(1) providing a reactive heat-curable one-component Polyurethane (PU) composition;

(2) providing an injection mold assembly defining a cavity and an injection port in communication with the cavity;

(3) injecting the reactive heat-curable one-component PU composition into the cavity at a temperature of about 40 ℃ to about 60 ℃, preferably 50 ℃ to 60 ℃, and a pressure of at most 10 bar, preferably at most 8 bar, more preferably at most 6 bar, to fill the cavity; and

(4) curing the reactive heat-curable one-component PU composition by heating the injection mold assembly at a temperature of less than 150 ℃ to form a molded article.

2. The process according to claim 1, wherein the heat-curable one-component polyurethane composition comprises a latent hardener, preferably an encapsulated polyisocyanate, and a resin, preferably comprising or consisting of at least one polyol and/or polyamine.

3. The process according to claim 1 or 2, wherein the reactive heat-curable one-component polyurethane composition is flowable at 20 ℃, preferably having a viscosity of from 150Pas to 300 Pas.

4. The method of any one of claims 1 to 3, wherein the step of injecting the reactive heat-curable one-component PU composition into a cavity is at (i) a temperature of 50 ℃ to 60 ℃; and (ii) a pressure of from 1 bar to 6 bar.

5. The process according to any one of claims 1 to 4, wherein the step of curing the reactive heat-curable one-component PU composition is carried out at a temperature of from 100 ℃ to 140 ℃, preferably from 110 ℃ to 130 ℃.

6. The method according to any one of claims 1 to 5, wherein the duration of step (4) is at most 60 seconds, preferably from 10 to 40 seconds.

7. The method of claim 6, wherein step (4) is subdivided into a heating phase of 5 to 25 seconds and a residence time at the curing temperature of 5 to 15 seconds.

8. The method of any of claims 1-7, wherein the method further comprises the step of (5) cooling the injection mold assembly.

9. The method of claim 8, wherein a complete heating/curing/cooling cycle requires at most 65 seconds, preferably 30 to 60 seconds, more preferably comprises a heating phase of 5 to 25 seconds, a dwell time at curing temperature of 5 to 15 seconds, and a cooling phase of 5 to 25 seconds.

10. The process according to any one of claims 1 to 9, wherein steps (3), (4) and optionally step (5) together require at most 70 seconds, preferably 30 to 60 seconds.

11. The method of any one of claims 1 to 10, wherein the mold assembly comprises an article of manufacture and the reactive heat-curable one-component PU composition is cured in situ on the article of manufacture to provide an integral gasket thereon.

12. The method of claim 11, wherein the article of manufacture is selected from the group consisting of a cable, a connector, a sensor, and a printed circuit board.

13. Shaped article obtainable by the process according to any one of claims 1 to 12.

Examples

Experiments were conducted using TEMPRO plus D Vario 180 as a temperature control unit (temperature unit), OPL071 as a molding tool, Teroson 1510(Henkel) as a molding material, and a printed circuit board as an article of manufacture to be provided with an integral gasket. The molded inserts were tested using a PTFE release spray or equipped with a permanent release coating.

The plate was placed in a mold assembly and the mold was heated to a temperature of 60 ℃. The molding material is then injected into the injection mold assembly. The mold was heated to 115 ℃ to cure for 12 seconds and then cooled to 60 ℃ over 30 seconds. A cured shaped article is obtained that can be easily removed from the mold assembly.

The aging test of the shaped electronic articles was carried out at 85 ℃ and 85% relative humidity for 500 hours, no corrosion was observed and the full functionality was retained.