# US 4,891,071 A · Cementitious composite material with vacuum integrity at elevated temperatures

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

- Number: US 4,891,071 A
- Document ID: US4891071A
- Status: Granted
- Kind: A
- Application number: 06/673,841
- Filed: 1984-11-21
- Granted: 1990-01-02
- Earliest claimed: 1984-11-21
- Assignees: Cemcom Corporation
- Inventors: Randall P. Bright; Sean Wise; Mark L. MacKenzie
- Web page: https://patentgrep.com/patent/US4891071A

## CPC

- C04B 41/009: {characterised by the material treated}
- C04B 14/34: Metals {, e.g. ferro-silicon}
- C04B 41/4853: {Epoxides}
- C04B 41/488: {Other macromolecular compounds obtained otherwise than by reactions only involving unsaturated carbon-to-carbon bonds}
- C04B 41/63: Macromolecular compounds
- C04B 2111/00301: {Non-porous materials, e.g. macro-defect free [MDF] products}
- 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

## Abstract

The temperatures at which the cementitious composite materials described in U.S. Pat. No. 4,482,385 can be used as tool or mold materials are extended by a treatment which comprises heating said composite materials to a temperature sufficient to expel free and adsorbed water from the concrete portion of the cementitious composite and thereafter refilling the resulting pores with an organic monomer or prepolymer and then crosslinking said impregnant to form an organic polymeric network in the inorganic composite material.

## Claims

### Claim 1

In a process for producing an article comprising a high strength cementitious tooling/molding material containing a filler wherein a major constituent of the filler comprises stainless steel aggregate in a cementitious binder; and which exhibits vacuum integrity at temperatures up to about 350.degree. C.; the improvement which consists in heating said article to a temperature of at least about 300.degree. C. and up to the temperature at which said stainless steel aggregate oxidizes and for a time sufficient to develop surface porosity in said article, thereafter impregnating the surface portions of the resulting porous article with a crosslinkable organic prepolymer of a high termperature resistant resin and thereafter polymerizing and curing the polymer in the surface pores of said article to produce a product which exhibits vacuum integrity at temperatures up to about 350.degree. C. and with enhanced flexural strength at elevated temperatures as compared with an otherwise similar product without said impregnation with said prepolymer, polymerization and curing.

### Claim 2 (depends on 1)

The product of the process of claim 1.

### Claim 3 (depends on 1)

The process of claim 1 in which said prepolymer is a polyimide.

### Claim 4 (depends on 1)

The process of claim 1 in which said temperature is between 400 and 700.degree. C.

### Claim 5 (depends on 1)

The process of claim 1 in which said prepolymer is a carboxy-imide-modified novolac epoxy.

### Claim 6 (depends on 1)

The process of claim 1 in which said prepolymer is an epoxy.