# US 11,299,597 B2 · Flame retardant foam and manufacturing method of flame retardant foam

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- Number: US 11,299,597 B2
- Document ID: US11299597B2
- Status: Granted
- Kind: B2
- Application number: 16/467,961
- Filed: 2017-12-15
- Published: 2019-11-14
- Granted: 2022-04-12
- Earliest claimed: 2016-12-16
- Assignees: Eco Research Institute Ltd.
- Applicants: Eco Research Institute Ltd.
- Inventors: Masakazu Toda; Takehiro Yano
- Web page: https://patentgrep.com/patent/US11299597B2

## CPC

- C08J 9/0061: {characterized by the use of several polymeric components}
- C08J 9/0066: {Use of inorganic compounding ingredients}
- C08J 9/0038: {containing phosphorus}
- C08K 3/36: Silica
- C08L 1/02: Cellulose; Modified cellulose
- C08L 3/02: Starch; Degradation products thereof, e.g. dextrin
- C08L 23/12: Polypropene
- C08J 9/0023: {containing oxygen}
- C08J 9/0028: {containing nitrogen}
- C08J 9/04: using blowing gases generated by a previously added blowing agent
- C08J 9/12: by a physical blowing agent
- C08J 9/16: Making expandable particles
- C08J 2201/03: Extrusion of the foamable blend
- C08J 2303/00: Characterised by the use of starch, amylose or amylopectin or of their derivatives or degradation products
- C08J 2323/12: Polypropene
- C08J 2323/26: modified by chemical after-treatment
- C08J 2401/00: Characterised by the use of cellulose, modified cellulose or cellulose derivatives
- C08J 2401/02: Cellulose; Modified cellulose
- C08J 2403/02: Starch; Degradation products thereof, e.g. dextrin
- C08J 2423/12: Polypropene
- C08J 2423/26: modified by chemical after-treatment
- C08K 2003/323: {Ammonium polyphosphate}
- C08K 2003/325: {Calcium, strontium or barium phosphate}
- C08L 2205/035: containing four or more polymers in a blend
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

The flame retardant foam is a molded form of a mixture containing at least a cellulose containing powder, a hydrophilic polymer, a foamable thermoplastic resin, a flame retardant, and water. The mixture contains at least one of tricalcium phosphate or silica as a dispersant.

## Claims

### Claim 1

A flame retardant foam which is a molded form of a mixture containing at least a cellulose containing powder, a hydrophilic polymer, a foamable thermoplastic resin, a flame retardant, and water,
the cellulose containing powder being one of:
wood powder which contains cellulose and is obtained by pulverizing hardwoods and conifers;
paper powder which is obtained by pulverizing used paper, or
a combination of the wood powder and the paper powder,
the mixture containing at least one of tricalcium phosphate or silica as a dispersant,
an average particle size of the dispersant being within a range of 4 μm or more and 7 μm or less,
a bulk density of the dispersant in terms of a loose bulk density being 0.6 g/cm3 or lower when measured using a powder characteristics tester, and
a bulk density of the dispersant in terms of a packed bulk density being 1.0 g/cm3 or lower when measured using the powder characteristics tester mentioned above.

### Claim 2 (depends on 1)

The flame retardant foam according to claim 1, wherein
the flame retardant contains an inorganic phosphate.

### Claim 3 (depends on 1)

The flame retardant foam according to claim 1, wherein
the flame retardant contains at least ammonium polyphosphate and ammonium phosphate.

### Claim 4 (depends on 1)

The flame retardant foam according to claim 1, wherein
a mixing amount of the flame retardant with respect to a total amount of the mixture is within a range of 5 mass % or more and 20 mass % or less, and
a mixing amount of the dispersant with respect to a total amount of the mixture is within a range of 2 mass % or more and 8 mass % or less.

### Claim 5 (depends on 1)

The flame retardant foam according to claim 1, wherein
the mixture contains pentaerythritol.

### Claim 6 (depends on 1)

The flame retardant foam according to claim 1, wherein
the mixture contains melamine or a melamine compound.

### Claim 7 (depends on 1)

The flame retardant foam according to claim 1, wherein
the mixture contains anhydrous fumaric acid-modified polyolefin.

### Claim 8 (depends on 1)

A manufacturing method of the flame retardant foam according to claim 1, the method comprising:
a mixing step which prepares a mixture by mixing at least the cellulose containing powder, the hydrophilic polymer, the flame retardant, at least one of tricalcium phosphate or silica as the dispersant, and water;
a particle-forming step which makes the mixture obtained in the mixing step into particles; and
an extrusion and foaming step in which the particles obtained in the particle-forming step and the foamable thermoplastic resin are mixed and heated in an extruder and formed into a foam.

### Claim 9 (depends on 8)

The manufacturing method of a flame retardant foam according to claim 8, wherein
in the mixing step, the flame retardant is an inorganic phosphate containing at least ammonium polyphosphate and ammonium phosphate, and
the ammonium phosphate is dissolved in water in advance before mixing.

### Claim 10 (depends on 8)

The manufacturing method of a flame retardant foam according to claim 8, wherein
water is further added in the extrusion and foaming step.