Method for the continuous fabrication of cellular products of thermohardenable resin

Claim 2

A process for the manufacture of blankets or sheets of expanded phenolic resin having a hard skin on each side in which an expandable liquid mixture comprising a resol resin, a volatile liquid blowing agent and a surface active agent is deposited on a moving surface and expanded and hardened, which process comprises: (a) depositing the expandable liquid mixture at a temperature of less than about 23° C. on an unheated moving surface with means by which said mixture becomes substantially uniform in thickness; (b) expanding the substantially uniformly thick liquid mixture by heating said mixture to a temperature of about 30° C. to about 60° C. as it passes through a second zone on the moving surface, the outer surface of the upper side of the expanded mixture being sticky, maintaining the expanded mixture in said second zone until said sticky condition has disappeared, thereby signifying that the mixture is completely expanded and is partially hardened and until said mixture is characterized by a considerable hardening at its center as well as by a state of good flexibility of the outer surface of its upper side; and thereafter (c) forming the completely expanded mixture between the moving surface and a second surface that is above and substantially parallel to the moving surface at a temperature higher than step (b) and completing the hardening of the expanded mixture.

Claim 3

A process according to claim 1 in which in step (b) the lateral surfaces of the expandable mixture are prevented from expanding by side belts.

Claim 4

A process according to claim 2 in which at the beginning of step (c) the lateral surfaces of the completely expanded phenolic resin mixture are formed between two side rollers.

Claim 5

A process according to claims 1 or 3 in which the volatile liquid blowing agent consists of pentanes.

Claim 6

A process according to claims 1 or 3 in which the surface active agent consists of one or more compounds from the group consisting of copolymers of siloxane and alkylene oxide, aliphatic monoesters of polyoxyethylene sorbitan, and polyoxyethylene glycerides.

Claim 7

A process according to claims 1 or 3 in which a distribution comb is placed above the unheated moving surface in step (a) to facilitate the setting of the expandable liquid mixture to a uniform thickness.

Claim 8

A process according to claims 1 or 3 in which the expandable liquid mixture is subjected to increasing temperatures as it is carried on the moving surface and expanded and hardened.

Claim 9

A process according to claim 7 in which the expandable liquid mixture is subjected to increasing temperatures by heating at least one of its sides.

Claim 10

A process according to claim 1 or 3 in which the complete expansion and hardening of the expandable liquid mixture is achieved as it is carried on the moving surface by heating the surface of the mixture.

Claim 11

A process according to claims 1 or 3 in which the temperature selected in the range of about 30° C. to 60° C. that can be used in step (b) is a function of the thickness and volume of the fully expanded and hardened phenolic resin mixture.

Claim 12

A process according to claims 1 or 3 in which step (b) ends between three and six minutes after complete disappearance of said sticky condition of the outer layer of the upper side of the sheet of completely expanded mixture.

Claim 13

A process according to claims 1 or 3 in which the temperature in step (c) is maintained between 50° C. and 70° C.

Claim 14

A process according to claims 1 or 3 in which in step (c) the distance between the moving surface and the second surface that is above and substantially parallel to the moving surface is fixed at between 0.5 mm and 2.0 mm less than the sheet of fully expanded mixture.

Claim 15

A process according to claims 1 or 3 in which after completing step (c), the sheet of completely expanded and hardened phenolic resin mixture is dried at a temperature between about 110° C. and 120° C.

Claim 16

A process for the continuous fabrication of blankets or sheets of hardened expanded phenolic resin with upper, lower, and lateral sides having a hard surface skin and a center with a lower density than said skin, said process comprising: (A) depositing an expandable liquid mixture comprising a resole resin, a blowing agent, and a hardening catalyst at a temperature of less than about 23° C. onto an unheated lower moving surface having a means by which said mixture is made substantially uniform in thickness and between unheated side belts in contact with, above, and perpendicular to, the lower moving surface, said belts moving at the same speed and in the same direction as the lower moving surface, and after the mixture has become substantially uniform in thickness; then (B) expanding said substantially uniformly thick liquid mixture at a temperature of about 30° C. to about 60° C. as it advances on the lower moving surface, the outer surface of the upper side of the mixture being sticky, then continuing this expansion step until said sticky condition has disappeared, thereby signifying that the mixture is expanded completely and hardened partially and until said mixture is characterized by a considerable hardening at its center as well as having a state of good flexbility on the outer surface of the upper side; (C) forming the completely expanded and partially hardened mixture between the lower moving surface, a second surface that is above and substantially parallel to the lower surface and side drums in contact with, perpendicular to, and moving at the same speed and in the same direction as the lower and upper surfaces, said forming step occurring as the mixture advances on the lower surface and at a temperature higher than the temperature recited in step (B); and (D) completing the hardening of the expanded mixture to form sheets of expanded hardened phenolic resin.

Claim 17

A process for the continuous fabrication of blankets or sheets of hardened expanded phenolic resin with upper, lower, and lateral sides having a hard surface skin and a center with a lower density than said skin, said process comprising: (A) depositing an expandable liquid mixture comprising a resole resin, a blowing agent, and a hardening catalyst at a temperature of less than about 23° C. onto an unheated lower moving surface having a means by which said mixture is made substantially uniform in thickness and between unheated side belts in contact with, above, and perpendicular to, the lower moving surface, said belts moving at the same speed and in the same direction as the lower moving surface, and after the mixture has become substantially uniform in thickness; then (B) expanding said substantially uniformly thick liquid mixture at a temperature of about 30° C. to about 60° C. as it advances on the lower moving surface, the outer surface of the upper side of the mixture being sticky, then continuing this expansion step until said sticky condition has disappeared, thereby signifying that the mixture is expanded completely and hardened partially and until said mixture is characterized by a considerable hardening at its center as well as having a state of good flexbility on the outer surface of the upper side; (C) forming the completely expanded and partially hardened mixture between the lower moving surface, a second surface that is above and substantially parallel to the lower surface and side drums in contact with, perpendicular to, and moving at the same speed and in the same direction as the lower and upper surfaces, said forming step occurring as the mixture advances on the lower surface and at a temperature higher than the temperature recited in step (B); and (D) completing the hardening of the expanded mixture to form sheets of expanded hardened phenolic resin.

Claim 18

A process according to claim 15 in which the liquid mixture also comprises a surface active agent and the blowing agent is a volatile liquid blowing agent.

Claim 19

A process according to claim 16 in which the surface active agent consists essentially of one or more compounds from the group consisting of copolymers of siloxane and alkylene oxide, aliphatic monoesters of polyoxyethylene sorbitan, and polyoxyethylene glycerides.

Claim 20

A process according to claim 16 in which the hardening catalyst is hydrochloric acid.

Claim 21

A process according to claim 16 in which the means by which said mixture is made substantially uniform in thickness in step (A) is a distribution comb placed above the unheated lower moving surface.

Claim 22

A process according to claim 16 in which the blowing agent is a technical pentane containing about 25% iso-pentane.

Claim 23

A process according to claim 16 in which step (B) ends between about 3 minutes and about 6 minutes after complete disappearance of the sticky condition of the outer surface of the upper side of the sheet of completely expanded mixture.

Claim 24

A process according to claim 16 in which the temperature in step (C) is between about 50° C. and about 70° C.

Claim 25

A process according to claim 16 in which in step (C) the distance between the lower moving surface and the second surface is between about 0.5 mm and about 2.0 mm less than the sheet of fully expanded mixture.

Claim 26

A process according to claim 16 in which after completing step (C) the sheet of completely expanded and hardened phenolic resin mixture is dried at a temperature of between about 110° C. and about 120° C.