Method for coating a polymeric article with a thermochromic paint

• US 4,228,761 A
• Filed: 09/14/1978
• Issued: 10/21/1980
• Est. Priority Date: 09/14/1978
• Status: Expired due to Term

• Current Assignee: Raychem Corporation (TE Connectivity Limited)
• Original Assignee: Raychem Corporation (TE Connectivity Limited)
• Inventors: Glover, Leon C., Lopez, Eugene F.
• Primary Examiner(s): Gron, Teddy S.
• Application Number:
  US05/942,295
• Time in Patent Office: 768 Days
• Field of Search: 252/408, 73/356, 73/17 R, 73/150 R, 73/150 A, 106/19, 106/308 B, 106/308 M, 106/308 S, 116/207, 116/201, 116/216, 428/539, 428/411, 428/347, 428/349, 206/459, 206/484
• US Class Current: 116/201
• CPC Class Codes: B29C 61/06 Making preforms having internal stresses, e.g. plastic memory
• CPC Class Codes: C09D 5/26 Thermosensitive paints
• CPC Class Codes: G01K 11/12 using changes in colour, translucency or reflectance
• CPC Class Codes: H02G 15/1806 Heat shrinkable sleeves insulation of electrical connections using a heat shrinking insulating sleeve H01R4/72
• CPC Class Codes: Y10S 252/962 Temperature or thermal history
• CPC Class Codes: Y10T 428/2826 Synthetic resin or polymer

Abstract

An improved method for indicating the temperature to which a heat-deformable polymeric material coated with a thermochromic paint has been heated is disclosed. The improvement comprises the addition to the thermochromic paint of a non-thermochromic compound selected from the group consisting of the sulfates, hydrated sulfates and nitrides of boron, aluminum, tin, lead, arsenic, antimony, bismuth, zinc and phosphorus; the sulfides and hydrated sulfides of boron, aluminum, bismuth and phosphorus; the oxides and hydrated oxides of boron, arsenic, antimony and phosphorus and the salts, organic derivatives and free acids of the oxyanions of boron, arsenic, antimony and phosphorus.

Claims

1. In a method for indicating the temperature to which a heat-deformable polymeric material subject to oxidative degradation is heated comprising the step of applying a thermochromic paint thereon, the thermochromic paint containing a thermochromic pigment comprising a metallic compound, the improvement comprising the step of inhibiting degradation of the polymeric material by adding to the paint a non-thermochromic compound in amounts effective to inhibit degradation of said polymeric material by the thermochromic pigment, said non-thermochromic compound selected from the group consisting of the sulfates, hydrated sulfates and nitrides of boron, aluminum, tin, lead, arsenic, antimony, bismuth, zinc and phosphorus;

the sulfides and hydrated sulfides of boron, aluminum, bismuth and phosphorus;

antimony;

the salts, organic derivatives and free acids of the oxyanions of boron, arsenic, and antimony; and

the oxides, salts and organic derivatives of the oxyanions of phosphorus.

3. The method of claim 1 or 2 wherein the thermochromic pigment is a transition metal compound.

4. The method of claim 3 wherein the thermochromic pigment is a hydrated iron oxide.

5. The method of claim 3 wherein the thermochromic pigment is a hydrated copper carbonate.

6. The method of claim 1 or wherein said non-thermochromic compound comprises from 0.5 to 10% by weight of the paint composition.

7. The method of claim 6 wherein said non-thermochromic compound comprises from 3 to 7% of the paint composition.

8. The method of claim 1 wherein the non-thermochromic compound is an oxygen containing boron compound selected from the group consisting of boron trioxide, borate salts, metaborate salts or boric acid.

9. The method of claim 1 wherein the non-thermochromic compound is an oxygen containing phosphorus compound selected from the group consisting of salts, and organic derivatives of phosphate and phosphite anions.

10. The method of claim 1 wherein the non-thermochromic compound is selected from the group consisting of antimony oxide and arsenic pentoxide.

11. The method of claim 1 or 2 including the step of heating the polymeric material until the thermochromic pigment changes color.

2. In a method for indicating the temperature to which a heat-deformable polymeric material subject to oxidative degradation is heated comprising the step of applying a thermochromic coating paint thereon, said coating paint containing a thermochromic pigment comprising a metallic compound, the improvement comprising the step of inhibiting degradation of the polymeric material by adding a non-thermochromic compound in amounts effective to inhibit degradation of said polymeric material by the thermochromic pigment, said non-thermochromic compound selected from the group consisting of the oxides and hydrated oxides of phosphorus and the salts, organic derivatives and free acids of the oxyanions of phosphorus.