Material in sheet form, convertible into a finished product by moulding-stamping or heat-shaping, comprising reinforcing fibers and a thermoplastics resin in power form, and process for preparing said material

Claim 2

A process for preparing a homogeneous reinforced thermoplastic sheet using papermaking techniques which comprises the steps of: a. preparing a basic homogeneous mixture consisting essentially of from about 80 to 40% by weight of the basic mixture of a powdered thermoplastic resin having a particle size of up to about 500 microns and about 20 to 60% by weight fibers of the same average length selected from the group consisting of mineral fibers, metallic fibers and synthetic organic fibers having a melting point at least about 50° C. higher than the melting point of the thermoplastic resin; b. adding about 5 to 25% by weight of the basic mixture of a polyolefin pulp having a specific surface area greater than about 1 m 2 /g; about 5 to 30% by weight of the basic mixture of a binding agent selected from the group consisting of latexes and polyvinyl alcohol fibers having a solubilizing temperature lower than 100° C. and about 0.2 to 10% by weight of the basic mixture of at least one flocculating agent; c. allowing the homogeneous mixture to flocculate; d. admitting the homogeneous mixture onto a wire screen as a single homogeneous layer; e. dewatering the homogeneous mixture; f. drying the resulting self-supporting homogeneous sheet to form a moldable reinforced thermoplastic sheet having a homogeneous composition.

Claim 3

A process for preparing a homogeneous heat-pressure product using papermaking techniques which comprises the steps of: a. preparing a basic homogeneous mixture consisting essentially of from about 80 to 40% by weight of the basic mixture of a powdered thermoplastic resin having a particle size of up to about 500 microns and about 20 to 60% by weight fibers of the same average length selected from the group consisting of mineral fibers, metallic fibers and synthetic organic fibers having a melting point at least about 50° C. higher than the melting point of the thermoplastic resin; b. adding about 5 to 25% by weight of the basic mixture of a polyolefin pulp having a specific surface area greater than about 1 m 2 /g; about 5 to 30% by weight of the basic mixture of a binding agent selected from the group consisting of latexes and polyvinyl alcohol fibers having a solubilizing temperature lower than 100° C. and about 0.2 to 10% by weight of the basic mixture of at least one flocculating agent; c. allowing the homogeneous mixture to flocculate; d. admitting the homogeneous mixture onto a wire screen as a single homogeneous layer; e. dewatering the homogeneous mixture; f. drying the resulting self-supporting homogeneous sheet to form a moldable reinforced thermoplastic sheet having a homogeneous composition; g. heating a stack containing one or more thermoplastic sheets to a temperature sufficient to cause melting of the thermoplastic resin and the polyolefin pulp.

Claim 4

A process for preparing a homogeneous heat-pressure product using papermaking techniques which comprises the steps of: a. preparing a basic homogeneous mixture consisting essentially of from about 80 to 40% by weight of the basic mixture of a powdered thermoplastic resin having a particle size of up to about 500 microns and about 20 to 60% by weight fibers of the same average length selected from the group consisting of mineral fibers, metallic fibers and synthetic organic fibers having a melting point at least about 50° C. higher than the melting point of the thermoplastic resin; b. adding about 5 to 25% by weight of the basic mixture of a polyolefin pulp having a specific surface area greater than about 1 m 2 /g; about 5 to 30% by weight of the basic mixture of a binding agent selected from the group consisting of latexes and polyvinyl alcohol fibers having a solubilizing temperature lower than 100° C. and about 0.2 to 10% by weight of the basic mixture of at least one flocculating agent; c. allowing the homogeneous mixture to flocculate; d. admitting the homogeneous mixture onto a wire screen as a single homogeneous layer; e. dewatering the homogeneous mixture; f. drying the resulting self-supporting homogeneous sheet to form a moldable reinforced thermoplastic sheet having a homogeneous composition; g. heating a stack containing one or more thermoplastic sheets to a temperature sufficient to cause melting of the thermoplastic resin and the polyolefin pulp.

Claim 5

A process for preparing a homogeneous heat-pressure molded product using papermaking techniques which comprises the steps of: a. preparing a basic homogeneous mixture consisting essentially of from about 80 to 40% by weight of the basic mixture of a powdered thermoplastic resin having a particular size of up to about 500 microns and about 20 to 60% by weight fibers of the same average length selected from the group consisting of mineral fibers, metallic fibers and synthetic organic fibers having a melting point at least about 50° C. higher than the melting point of the thermoplastic resin; b. adding about 5 to 25% by weight of the basic mixture of a polyolefin pulp having a specific surface area greater than about 1 m 2 /g; about 5 to 30% by weight of the basic mixture of a binding agent selected from the group consisting of latexes and polyvinyl alcohol fibers having a solubilizing temperature lower than 100° C. and about 0.2 to 10% by weight of the basic mixture of at least one flocculating agent; c. allowing the homogeneous mixture to flocculate; d. admitting the homogeneous mixture onto a wire screen as a single homogeneous layer; e. dewatering the homogeneous mixture; f. drying the resulting self-supporting homogeneous sheet to form a moldable reinforced thermoplastic sheet having a homogeneous composition; g. heating a stack containing one or more thermoplastic sheets to a temperature sufficient to cause melting of the thermoplastic resin and a polyolefin pulp; h. molding the heated stack under pressure to achieve a homogeneous molded product.

Claim 6

A process for preparing a homogeneous heat-pressure molded product using papermaking techniques which comprises the steps of: a. preparing a basic homogeneous mixture consisting essentially of from about 80 to 40% by weight of the basic mixture of a powdered thermoplastic resin having a particular size of up to about 500 microns and about 20 to 60% by weight fibers of the same average length selected from the group consisting of mineral fibers, metallic fibers and synthetic organic fibers having a melting point at least about 50° C. higher than the melting point of the thermoplastic resin; b. adding about 5 to 25% by weight of the basic mixture of a polyolefin pulp having a specific surface area greater than about 1 m 2 /g; about 5 to 30% by weight of the basic mixture of a binding agent selected from the group consisting of latexes and polyvinyl alcohol fibers having a solubilizing temperature lower than 100° C. and about 0.2 to 10% by weight of the basic mixture of at least one flocculating agent; c. allowing the homogeneous mixture to flocculate; d. admitting the homogeneous mixture onto a wire screen as a single homogeneous layer; e. dewatering the homogeneous mixture; f. drying the resulting self-supporting homogeneous sheet to form a moldable reinforced thermoplastic sheet having a homogeneous composition; g. heating a stack containing one or more thermoplastic sheets to a temperature sufficient to cause melting of the thermoplastic resin and a polyolefin pulp; h. molding the heated stack under pressure to achieve a homogeneous molded product.

Claim 7

A process for preparing a homogeneous reinforced thermoplastic sheet using papermaking techniques which comprises the steps of: a. preparing a basic homogeneous mixture consisting essentially of from about 80 to 5% by weight of the basic mixture of a powdered thermoplastic resin having a particular size of up to about 500 microns and about 20 to 95% by weight fibers of the same average length selected from the group consisting of mineral fibers, metallic fibers and synthetic organic fibers having a melting point at least about 50° C. higher than the melting point of the thermoplastic resin; b. adding about 5 to 25% by weight of the basic mixture of a polyolefin pulp having a specific surface area greater than about 1 m 2 /g; about 5 to 30% by weight of the basic mixture of a binding agent selected from the group consisting of latexes and polyvinyl alcohol fibers having a solubilizing temperature lower than 100° C. and about 0.2 to 10% by weight of the basic mixture of at least one flocculating agent; c. allowing the homogeneous mixture to flocculate; d. admitting the homogeneous mixture onto a wire screen as a single homogeneous layer; e. dewatering the homogeneous mixture; f. drying the resulting self-supporting homogeneous sheet to form a moldable reinforced thermoplastic sheet having a homogeneous composition.

Claim 8

A process for preparing a homogeneous reinforced thermoplastic sheet using papermaking techniques which comprises the steps of: a. preparing a basic homogeneous mixture consisting essentially of from about 80 to 5% by weight of the basic mixture of a powdered thermoplastic resin having a particular size of up to about 500 microns and about 20 to 95% by weight fibers of the same average length selected from the group consisting of mineral fibers, metallic fibers and synthetic organic fibers having a melting point at least about 50° C. higher than the melting point of the thermoplastic resin; b. adding about 5 to 25% by weight of the basic mixture of a polyolefin pulp having a specific surface area greater than about 1 m 2 /g; about 5 to 30% by weight of the basic mixture of a binding agent selected from the group consisting of latexes and polyvinyl alcohol fibers having a solubilizing temperature lower than 100° C. and about 0.2 to 10% by weight of the basic mixture of at least one flocculating agent; c. allowing the homogeneous mixture to flocculate; d. admitting the homogeneous mixture onto a wire screen as a single homogeneous layer; e. dewatering the homogeneous mixture; f. drying the resulting self-supporting homogeneous sheet to form a moldable reinforced thermoplastic sheet having a homogeneous composition.

Claim 9

A homogeneous reinforced thermoplastic sheet prepared using papermaking techniques which comprises the steps of: a. preparing a basic homogeneous mixture consisting essentially of from about 80 to 40% by weight of the basic mixture of a powdered thermoplastic resin having a particle size of up to about 500 microns and about 20 to 60% by weight fibers of the same average length selected from the group consisting of mineral fibers, metallic fibers and synthetic organic fibers having a melting point at least about 50° C. higher than the melting point of the thermoplastic resin; b. adding about 5 to 25% by weight of the basic mixture of a polyolefin pulp having a specific surface area greater than about 1 m 2 /g; about 5 to 30% by weight of the basic mixture of a binding agent selected from the group consisting of latexes and polyvinyl alcohol fibers having a solubilizing temperature lower than 100° C. and about 0.2 to 10% by weight of the basic mixture of at least one flocculating agent; c. allowing the homogeneous mixture to flocculate; d. admitting the homogeneous mixture onto a wire screen as a single homogeneous layer; e. dewatering the homogeneous mixture; f. drying the resulting self-supporting homogeneous sheet to form a moldable reinforced thermoplastic sheet having a homogeneous composition.

Claim 10

A homogeneous reinforced thermoplastic sheet prepared using papermaking techniques which comprises the steps of: a. preparing a basic homogeneous mixture consisting essentially of from about 80 to 40% by weight of the basic mixture of a powdered thermoplastic resin having a particle size of up to about 500 microns and about 20 to 60% by weight fibers of the same average length selected from the group consisting of mineral fibers, metallic fibers and synthetic organic fibers having a melting point at least about 50° C. higher than the melting point of the thermoplastic resin; b. adding about 5 to 25% by weight of the basic mixture of a polyolefin pulp having a specific surface area greater than about 1 m 2 /g; about 5 to 30% by weight of the basic mixture of a binding agent selected from the group consisting of latexes and polyvinyl alcohol fibers having a solubilizing temperature lower than 100° C. and about 0.2 to 10% by weight of the basic mixture of at least one flocculating agent; c. allowing the homogeneous mixture to flocculate; d. admitting the homogeneous mixture onto a wire screen as a single homogeneous layer; e. dewatering the homogeneous mixture; f. drying the resulting self-supporting homogeneous sheet to form a moldable reinforced thermoplastic sheet having a homogeneous composition.

Claim 11

The process as described in claim 1, wherein the molding is accomplished by a method selected from the group consisting of stamp molding or heat stamping.

Claim 12

The process as described in claim 1, 2 or 3, wherein the aqueous mixture is prepared by adding successively in order a dispersing agent, reinforcing fibers, polyolefin pulp, thermoplastic resin, a portion of the flocculating agent, binding agent and the remaining flocculating agent.

Claim 13

The process as described in claim 1, 2 or 3, wherein the aqueous mixture in step a is allowed to flocculate in a concentrate form and is then diluted with water so as to obtain aqueous suspension containing about 0.01 to 5% by weight of solids.

Claim 14

The process as described in claim 8, wherein the mixture is acidified during dilution to about pH 2 to pH 4.

Claim 15

The process as described in claim 9, wherein sulfuric acid is used to acidify the mixture.