Macro defect free cement with improved moisture resistance

Patent metadata

Field	Value
Publication number	US-2016221871-A1
Application number	US-201514610469-A
Country	US
Kind code	A1
Filing date	Jan 30, 2015
Priority date	Jan 30, 2015
Publication date	Aug 4, 2016
Grant date	—

Abstract

A cementitious composition may include polyvinyl alcohol, high alumina cement, water, a metallic coagent, a peroxide crosslinking initiator, and an organic acid retardant. A molded article may be manufactured from the cementitious composition by preparing a hydrogel pre-polymer blend of saponified polyvinyl alcohol acetate (PVAA) with greater than or equal to approximately 85% saponified PVAA, and water, mixing the hydrogel pre-polymer blend with high alumina cement (HAC) using a high shear mixing process, mixing in a metallic coagent and a peroxide crosslinking initiator, mixing in an organic acid retardant, and hot press molding the mixture.

First claim

What is claimed is:

1 . A cementitious composition, comprising:
polyvinyl alcohol;
high alumina cement;
water;
a metallic coagent; and
a peroxide crosslinking initiator.

2 . The cementitious composition of claim 1 , wherein proportions of ingredients of the composition by weight comprise:
90-110 parts polyvinyl alcohol; 150-250 parts water; 1200-3000 parts high alumina cement (HAC); 30-100 parts metallic coagent; and 3-30 parts peroxide crosslinking agent.

3 . The cementitious composition of claim 1 , wherein the metallic coagent is a metal-bound reactive monomer that is reacted with peroxides.

4 . The cementitious composition of claim 3 , wherein the metallic coagent is selected from the group comprising: zinc diacrylate (ZDA), zinc monoacrylate (ZMA), zinc dimethacrylate (ZDMA), calcium diacrylate (CDA), aluminum triacrylate, and magnesium diacrylate.

5 . The cementitious composition of claim 1 , wherein the peroxide crosslinking initiator is selected from the group comprising: dicumyl peroxide (tradename DI-CUP), a,a′-bis(tert-butylperoxy)diisopropylbenzene (tradename VUL-CUP), 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane (tradename LUPEROX 231), n-butyl-4,4-di(t-butylperoxy)valerate (tradename LUPEROX 230), and lower-temperature peroxides such as methyl ethyl ketone peroxide (MEKP) and hydrogen peroxide.

6 . The cementitious composition of claim 1 , wherein the polyvinyl alcohol is a saponified polyvinyl alcohol acetate (PVAA) with a saponification level of greater than or equal to about 85%.

7 . The cementitious composition of claim 1 , further including an organic acid retardant.

8 . The cementitious composition of claim 2 , further including 10-30 parts by weight of an organic acid retardant selected from the group comprising: acetic acid, citric acid, tartartic acid, succinic acid, and polymeric acids such as polyacrylic acid.

9 . A molded article made from a macro-defect-free (MDF) cementitious composition comprising:
polyvinyl alcohol; high alumina cement; water; a metallic coagent; and a peroxide crosslinking agent.

10 . The molded article of claim 9 , wherein proportions of ingredients of the MDF cementitious composition by weight comprise:
90-110 parts polyvinyl alcohol; 150-250 parts water; 1200-3000 parts high alumina cement (HAC); 30-100 parts metallic coagent; and 3-30 parts peroxide crosslinking agent.

11 . The molded article of claim 9 , wherein the metallic coagent is a metal-bound reactive monomer that may be reacted with peroxides.

12 . The molded article of claim 9 , wherein the metallic coagent is selected from the group comprising: zinc diacrylate (ZDA), zinc monoacrylate (ZMA), zinc dimethacrylate (ZDMA), calcium diacrylate (CDA), aluminum triacrylate, and magnesium diacrylate.

13 . The molded article of claim 9 , wherein the peroxide crosslinking agent is selected from the group comprising: dicumyl peroxide (tradename DI-CUP), a,a′-bis(tert-butylperoxy)diisopropylbenzene (tradename VUL-CUP), 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane (tradename LUPEROX 231), n-butyl-4,4-di(t-butylperoxy)valerate (tradename LUPEROX 230), and lower-temperature peroxides such as methyl ethyl ketone peroxide (MEKP) and hydrogen peroxide.

14 . The molded article of claim 9 , wherein the polyvinyl alcohol is a saponified polyvinyl alcohol acetate (PVAA) with saponification levels of greater than or equal to about 85%.

15 . The molded article of claim 9 , wherein the flexural strength of the molded article after approximately 4 weeks of immersion of the molded article in water retains at least 70% of the flexural strength of the molded article immediately after the article is molded and cured.

16 . The molded article of claim 9 , wherein the modulus of elasticity of the molded article after approximately 4 weeks of immersion of the molded article in water retains at least 50% of the modulus of elasticity of the molded article immediately after the article is molded and cured.

17 . A method of manufacturing a molded article made from a MDF cementitious composition, the method comprising:
preparing a hydrogel pre-polymer blend of saponified polyvinyl alcohol acetate (PVAA) with greater than or equal to about 85% saponified PVAA, and water; mixing the hydrogel pre-polymer blend with high alumina cement (HAC) using a high shear mixing process; mixing in a metallic coagent and a peroxide crosslinking initiator; mixing in an organic acid retardant; and hot press molding the mixture.

18 . The method of claim 17 , further including:
extruding the mixture to form the molded article; and post curing the molded article at a temperature of approximately 90 degrees C. for approximately 24 hours.

19 . The method of claim 17 , wherein the hydrogel pre-polymer blend is produced from a ratio of polymer:water in the range from approximately 100:75 to 100:150.

20 . The method of claim 17 , wherein the proportions of ingredients of the MDF cementitious composition by weight comprise:
90-110 parts polyvinyl alcohol; 150-250 parts water; 1200-3000 parts high alumina cement (HAC); 30-100 parts metallic coagent; and 3-30 parts peroxide crosslinking agent.

Assignees

• Caterpillar Inc

Inventors

• Amstutz Aaron K

Classifications

• B29K2029/04

  PVOH, i.e. polyvinyl alcohol (B29K2031/04 takes precedence) · CPC title

• C04B7/32 Primary

  Aluminous cements · CPC title

• B29C47/0004

  Operations & Transport · mapped topic

• C04B28/06 Primary

  Aluminous cements (monolithic refractories or refractory mortars C04B35/66) · CPC title

• C04B24/2623

  Polyvinylalcohols; Polyvinylacetates · CPC title