# US 2021/0276074 A1 · Smoke-suppressing additive for polyurethane-forming binder system

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- Number: US 2021/0276074 A1
- Document ID: US20210276074A1
- Status: Published application
- Kind: A1
- Application number: 16/807,638
- Filed: 2020-03-03
- Published: 2021-09-09
- Earliest claimed: 2020-03-03
- Assignees: ASK Chemicals GmbH
- Applicants: ASK Chemicals LLC
- Inventors: Paula Vivas; Matthew Shoffner; Lee Horvath
- Web page: https://patentgrep.com/patent/US20210276074A1

## CPC

- B22C 1/2273: {Polyurethanes; Polyisocyanates}
- B22C 1/02: characterised by additives for special purposes, e.g. indicators, breakdown additives
- C04B 26/16: Polyurethanes
- C08K 3/22: of metals
- C04B 2111/0087: {for metallurgical applications}
- C04B 2111/00939: {for the fabrication of moulds or cores}
- C08K 2003/2268: {Ferrous oxide (FeO)}
- C08K 2003/2272: {Ferric oxide (Fe2O3)}
- C08K 2003/2275: {Ferroso-ferric oxide (Fe3O4)}
- B22C: FOUNDRY MOULDING (moulding refractory materials in general B28B)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

A sand additive for use in a “no bake” foundry mix composition having a polyurethane-based binder system reduces the amount of smoke emitted when molds and cores formed from the composition are exposed to molten metal, as compared to when the sand additive is not used. The sand additive comprises yellow iron oxide having the chemical formula Fe(OH)3. It can also comprise at least one of red iron oxide, black iron oxide and wüstite. In such cases, the yellow iron oxide accounts for about 10 to about 40 weight percent of the combined weight of the yellow iron oxide, red iron oxide, black iron oxide and wüstite, and preferably, about 20 to about 30 weight percent of the combined weight of the yellow iron oxide, red iron oxide, black iron oxide and wüstite.

## Claims

### Claim 1

A foundry mix composition, comprising:
a polyurethane binder precursor, provided in two parts, the first part comprising a polyol component and the second part comprising a polyisocyanate component;
a liquid curing catalyst;
an appropriate foundry aggregate; and
a sand additive, comprising yellow iron oxide.

### Claim 2 (depends on 1)

The foundry mix composition of claim 1, wherein:
the liquid curing catalyst is present in the range of about 4 to about 8 weight percent based on the weight of the first part of the polyurethane binder component.

### Claim 3 (depends on 2)

The foundry mix composition of claim 2, wherein:
the liquid curing catalyst is kept separate from at least the second part of the polyurethane binder precursor until use.

### Claim 4 (depends on 1)

The foundry mix composition of claim 1, wherein:
the liquid curing catalyst is kept separate from at least the second part of the polyurethane binder precursor until use.

### Claim 5 (depends on 4)

The foundry mix composition of claim 4, wherein:
the sand additive further comprises at least one of red iron oxide, black iron oxide and wüstite.

### Claim 6 (depends on 1)

The foundry mix composition of claim 1, wherein:
the sand additive further comprises at least one of red iron oxide, black iron oxide and wüstite.

### Claim 7 (depends on 2)

The foundry mix composition of claim 2, wherein:
the sand additive further comprises at least one of red iron oxide, black iron oxide and wüstite.

### Claim 8 (depends on 3)

The foundry mix composition of claim 3, wherein:
the sand additive further comprises at least one of red iron oxide, black iron oxide and wüstite.

### Claim 9 (depends on 4)

The foundry mix composition of claim 4, wherein:
the sand additive further comprises at least one of red iron oxide, black iron oxide and wüstite.

### Claim 10 (depends on 1)

The foundry mix composition of claim 1, wherein:
the sand additive is present in the amount of about 3 to about 5 weight percent, based on the foundry aggregate.

### Claim 11 (depends on 6)

The foundry mix composition of claim 6, wherein:
the yellow iron oxide in the sand additive accounts for about 10 to about 40 weight percent of the combined weight of the yellow iron oxide, red iron oxide, black iron oxide and wüstite.

### Claim 12 (depends on 11)

The foundry mix composition of claim 11, wherein:
the yellow iron oxide in the sand additive accounts for about 20 to about 30 weight percent of the combined weight of the yellow iron oxide, red iron oxide, black iron oxide and wüstite.

### Claim 13 (depends on 1)

The foundry mix composition of claim 1, wherein:
The appropriate foundry aggregate is a silica sand.

### Claim 14

A sand additive for use in a “no bake” foundry mix composition to reduce smoke emissions, comprising yellow iron oxide.

### Claim 15 (depends on 14)

The sand additive of claim 14, further comprising:
at least one of red iron oxide, black iron oxide and wüstite.

### Claim 16 (depends on 15)

The sand additive of claim 15, wherein:
the yellow iron oxide in the sand additive accounts for about 10 to about 40 weight percent of the combined weight of the yellow iron oxide, red iron oxide, black iron oxide and wüstite.

### Claim 17 (depends on 15)

The sand additive of claim 15, wherein:
the yellow iron oxide in the sand additive accounts for about 20 to about 30 weight percent of the combined weight of the yellow iron oxide, red iron oxide, black iron oxide and wüstite.