# US 5,620,130 A · Process for producing a die plate for underwater granulation of plastic material with an intermediate nickel alloy layer

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,620,130 A
- Document ID: US5620130A
- Status: Granted
- Kind: A
- Application number: 08/500,630
- Filed: 1995-07-11
- Granted: 1997-04-15
- Earliest claimed: 1994-07-15
- Assignees: Werner & Pfleiderer
- Inventors: Friedrich Schneider; Wolfgang Worz
- Web page: https://patentgrep.com/patent/US5620130A

## CPC

- B29B 9/065: {under-water, e.g. underwater pelletizers}
- B29B 7/582: {for discharging, e.g. doors}
- B29B 7/826: {Apparatus therefor}
- B29B 9/06: in the form of filamentary material, e.g. combined with extrusion
- B29C 48/05: Filamentary, e.g. strands
- B29C 48/345: Extrusion nozzles comprising two or more adjacently arranged ports, for simultaneously extruding multiple strands, e.g. for pelletising
- B29C 48/04: Particle-shaped (making granules B29B9/00)
- B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)

## Abstract

A die plate for the underwater granulation of thermoplastic material is formed with a base plate of an iron alloy, a hard annular cutting plate of titanium-carbide alloy, and an intermediate buffer layer containing nickel between the base plate and the cutting plate to equilibrate heat stresses due to different coefficient of thermal expansion of the base and the cutting plates. The intermediate layer is formed with a thickness of between 0.5 and 2 mm by hot-isostatic pressing a nickel-containing metal powder between the plates such that the intermediate layer is diffusion welded to the plates. Two nickel layers with an intermediate titanium-containing plate can also be formed. Also an ansenitic layer can be formed between the nickel layer and the base plate.

## Claims

### Claim 1

A process for forming a die plate for underwater granulation of plastic material comprising:
providing a base plate,
providing an annular cutting plate in facing relation to said base plate, and
forming an intermediate layer between and joining said base plate and said annular cutting plate by hot-isostatic compression of a metal powder mixture containing nickel to diffusion bond the intermediate layer to said base plate and to said annular cutting plate.

### Claim 2 (depends on 1)

A process as claimed in claim 1, comprising forming said intermediate layer with a thickness between 0.5 and 2 mm.

### Claim 3 (depends on 2)

A process as claimed in claim 2, comprising providing bores in said intermediate layer and said cutting plate which communicate with feed channels for plastic material in said base plate such that the plastic material will be discharged as strands from the bores at an outer cutting surface of said cutting plate.

### Claim 4 (depends on 3)

A process as claimed in claim 3, wherein the nickel is the predominant fraction in said powder material.

### Claim 5 (depends on 4)

A process as claimed in claim 4, wherein said nickel is present in an amount of at least 90% by weight.

### Claim 6 (depends on 1)

A process as claimed in claim 1, wherein said intermediate layer is formed as an austenitic alloy with a nickel fraction of 8 to 15% by weight.

### Claim 7 (depends on 1)

A process as claimed in claim 1, wherein said intermediate layer is formed by first and second integrated layers, the first layer being diffusion bonded to said base plate and being formed as an austenitic alloy containing nickel, the second layer being diffusion bonded to said cutting plate and being formed as an alloy containing nickel in an amount of at least 90% by weight.

### Claim 8 (depends on 7)

A process as claimed in claim 7, wherein each of said first and second layers is formed with a thickness of between 0.5 and 2 mm.

### Claim 9 (depends on 1)

A process as claimed in claim 1, wherein said intermediate layer is formed by first, second and third layers, the first and third layers being respectively diffusion bonded to said base plate and said cutting plate and being formed as an alloy containing nickel in an amount of at least 90% by weight, the second layer being formed as an alloy containing titanium in an amount of at least 90% by weight.

### Claim 10 (depends on 9)

A process as claimed in claim 9, wherein each of said first, second and third layers is formed with a thickness of between 0.5 and 2 mm.