Abstract Methods and apparatus are provided for converting a base material such as paper, wood or concrete to a plastic composite material in which the steps of pressure impregnation of the base material with a monomer and polymerization of the monomer after impregnation by irradiation is accomplished in a single container. The apparatus includes an irradiation tank equipped with an irradiation absorbing fluid recirculation system for bacteria control and an inert gas system for displacing the irradiation absorbing fluid from between the submerged containers and the irradiation source. The methods described include placing a first canister containing composite material impregnated with a liquid monomer within radiation receiving proximity to the radiation source, irradiating through walls of the canister the impregnated material in the canister by an amount sufficient to effect partial polymerization of the monomer without raising the temperature to a disadvantageous level, and after partial polymerization of the monomer in the first canister, placing a second canister containing the material impregnated with a liquid monomer between the first canister and the radiation source whereby substantially only radiation passing through the second canister effects complete polymerization of the monomer in the first canister without further materially raising the temperature of the composite material therein.
The process of claim 1 further including rotating the first canister so as to present an opposite side thereof in radiation receiving proximity of the source prior to placing the second canister between the first canister and the source, and wherein the source of high energy gamma radiation is placed in a tank containing a radiation absorbing liquid into which the canisters are immersed for irradiation.
Claim 2
Dependent Claim
79 words
The process of claim 2 wherein the first and second canisters are rectangular and comprise two substantially parallel sidewalls each having an area of about 4 feet by 8 feet and a thickness of about 1 foot, and wherein the polymerization is effected by high energy irradiation through said parallel sidewalls, and wherein the radiation source is an elongated flat plaque having radioactive material placed in the form of discontinuous parallel rows extending across the surface of the plaque.
Claim 3
Dependent Claim
31 words
The process of claim 3 wherein the radiation absorbing liquid is water, and wherein the first canister is irradiated until the temperature of the wood therein is approximately 180* to 200*F.
Claim 4
Dependent Claim
48 words
The process of claim 1 wherein the second canister receives from 1.6 to 100 rads per second from the radiation source and wherein from 5 to 10 percent of the radiation received by the second canister passes through the second canister and is received by the first canister.
Claim 5
Dependent Claim
131 words
The process of claim 1 wherein said first canister is in a group comprising a first series of canisters all containing wood impregnated with a liquid monomer and which canisters are all caused to pass along a path within radiation receiving proximity of the radiation source; and wherein said second canister is in another group comprising a second series of canisters all containing wood impregnated with a liquid monomer and which canisters are all caused to pass along a path between the first series of canisters and the radiation source whereby substantially only radiation passing through the second series of canisters is received by the first series of canisters to effect further polymerization of the wood in said first series of canisters without raising the temperature to the moisture vaporization temperature.
Claim 6
Dependent Claim
68 words
The process of claim 6 further including rotating the first series of canisters so as to present an opposite side thereof in radiation receiving proximity of the source prior to placing the second canisters between the first canisters and the source, and wherein the source of high energy gamma radiation is placed in a tank containing a radiation absorbing liquid into which the canisters are immersed for irradiation.
Claim 7
Dependent Claim
22 words
The process of claim 6 wherein the first and second series of canisters are continuously and uniformly moving about the radiation source.
Claim 8
Dependent Claim
152 words
An improved process for the production of wood plastic composite material, which process comprises: submerging a first canister containing wood impregnated with a liquid monomer into a radiation absorbing liquid; moving the first canister into radiation receiving proximity to a source of gamma radiation submerged within the radiation absorbing liquid; irradiating through the walls of the canister the impregnated wood in the canister by an amount sufficient to effect partial polymerization of the monomer without raising the temperature of the wood to the vaporization temperature of moisture within the wood; and after partial polymerization of the monomer of the first canister, placing a second canister containing wood impregnated with a liquid monomer between the first canister and the radiation source whereby substantially only radiation passing through the second canister effects complete polymerization of the monomer in the first canister without raising the temperature of the wood therein to the moisture vaporization temperatUre.
Claim 9
Dependent Claim
55 words
The process of claim 9 wherein the source of radiation is submerged in a radiation absorbing liquid and including the steps of submerging said canisters into said liquid as they are ready for treatment at the irradiation station and of removing said canisters from said liquid when polymerization of the monomer has been substantially completed.