# US 4,395,529 A · Coating powders for protective films based on epsilon-caprolactam blocked isocyanates

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- Number: US 4,395,529 A
- Document ID: US4395529A
- Status: Granted
- Kind: A
- Application number: 06/285,353
- Filed: 1981-07-20
- Granted: 1983-07-26
- Earliest claimed: 1981-07-20
- Assignees: Cargill, Incorporated
- Inventors: K. A. Pai Panandiker; Charles Danick
- Web page: https://patentgrep.com/patent/US4395529A

## CPC

- C08G 18/42: Polycondensates having carboxylic or carbonic ester groups in the main chain
- C08G 18/757: {containing at least two isocyanate or isothiocyanate groups linked to the cycloaliphatic ring by means of an aliphatic group}
- C08G 18/8074: {Lactams}
- C08G 2150/20: Compositions for powder coatings
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

This invention describes a coating composition and method for producing such composition wherein the composition includes an E-caprolactam blocked polyisocyanate including a diisocyanate selected from the group consisting of 1,4-bis (isocyanatomethyl) cyclohexane and 1,3-bis (isocyanatomethyl) cyclohexane; and a film forming hydroxy containing organic polymer.

## Claims

### Claim 1

A coating composition which comprises a molar mixture of E-caprolactam blocked polyisocyanate and E-caprolactam blocked diisocyanate in a ratio in a range of about 1:0 to about 1:1.5,
said blocked polyisocyanate comprising the reaction product of a polyhydric compound and a diisocyanate,
said diisocyanate being selected from the group consisting of 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane and mixtures thereof,
said polyhydric compound being selected from the group consisting of trimethylol propane, trimethylol ethane, glycerine, E-caprolactone, and mixtures thereof; and
a film forming hydroxy containing polyester.

### Claim 2 (depends on 1)

A coating composition as recited in claim 1 wherein said mixture has free NCO of less than 0.8 percent by weight and an ICI melt viscosity of about 6 to about 20 poise at 175.degree. C.

### Claim 3 (depends on 1)

A coating composition as recited in claim 1 wherein said polyester is a reaction product of neopentyl glycol, cyclohexandimethanol, trimethylol propane and terephthalic acid.

### Claim 4 (depends on 1)

A coating composition as recited in claim 1 wherein said polyester has an ICI melt viscosity of about 15 to about 20 poise.

### Claim 5 (depends on 1)

A coating composition as recited in claim 1 wherein said mixture of E-caprolactam blocked polyisocyanate and blocked diisocyanate has an equivalent weight in the range from about 280 to about 320.

### Claim 6 (depends on 5)

A coating composition as recited in claim 5 wherein said mixture of E-caprolactam blocked polyisocyanate and blocked diisocyanate is the reaction product of about 3.5 moles diisocyanate, about one mole trimethylol propane and about 4 moles E-caprolactam.

### Claim 7

A coating composition which comprises: an E-caprolactam blocked polyisocyanate which is the reaction product of from about 3.0 to about 4.5 moles of a diisocyanate selected from the group consisting of 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane and mixtures thereof, about 1.0 mole of polyhydric compound per mole of isocyanate group, and from about 3.0 to about 6.0 moles of E-caprolactam:
said polyhydric compound being selected from the group consisting of trimethylol propane, trimethylol ethane, glycerine, E-caprolactone, and mixtures thereof; of
a film forming hydroxy containing a polyester.

### Claim 8

A method for producing a coating composition comprising:
reacting a reaction mixture comprising
from about 3.0 to about 4.5 moles of a diisocyanate selected from the group consisting of 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane and mixtures thereof,
about 1 mole of a polyhydric compound per mole of isocyanate group, said polyhydric compound being selected from the group consisting of trimethylol propane, trimethylol ethane, glycerine, E-caprolactone, and mixtures thereof,
and from about 3.0 to about 6.0 moles E-caprolactam to form a block polyisocyanate component;
mixing said blocked polyisocyanate compound with a film forming hydroxy containing polyester.