The present invention relates to fire resistive foamed polystyrene herein referred to as xe2x80x9cStyrofoamxe2x80x9d products and a method of their production.
One of typical examples of conventional methods of producing a Styrofoam product calls for producing partially formed beads by conducting preliminary forming of numerous styrene beads that have been produced by forming polystyrene into the shape of beads, and then, after leaving these pre-expanded beads to age, expanding them properly.
As conventional Styrofoam products having thus produced are not only light in mass but also non-hygroscopic, superbly heat insulating, easy to handle and very inexpensive, they enjoy a tremendous demand and are widely used in the field of ordinary houses, building materials, miscellaneous goods or the like.
Conventional Styrofoam products, however, have drawbacks such that they have little ability to withstand fire and, when exposed to fire, are easy to become contracted and deformed so that their entire shape collapses instantly.
In order to solve the above problem, the present invention relates to Styrofoam products that have superior fire resistance and are capable of limiting degree of contraction and deformation caused by fire. The present invention also relates to a method of producing such Styrofoam products.
A Styrofoam product according to the present invention includes one or more formed styrene beads and a coating film or coating films that contain boric acid-based inorganic materials and are formed on the surface(s) of the styrene bead(s). As a coating film or coating films containing boric acid-based inorganic materials are thus formed on the surface(s) of the formed styrene bead(s), the coating film(s) suppress burning of the styrene bead(s). In case a great quantity of heat is applied, the vitreous coat into which each coating film has chemically changed prevents the styrene bead from burning deeper. Therefore, the invention increases the heat resisting ability of the Styrofoam product and prevents its thermal contraction and deformation.
A Styrofoam product according to another feature of the present invention includes a plurality of styrene beads that have been expanded and solidly bonded to one another, and coating films that contain boric acid-based inorganic materials and are respectively formed on the surfaces of the styrene beads. As coating films containing boric acid-based inorganic materials are thus formed on the surfaces of the styrene beads, which have been expanded and solidly bonded to one another, the coating films suppress burning of the styrene beads. In case a great quantity of heat is applied, the vitreous coats into which the coating films have chemically changed prevent the styrene beads from burning deeper. The invention thus increases the heat resisting ability of the Styrofoam product and prevents its thermal contraction and deformation.
A method of producing a Styrofoam product according to the invention calls for producing a beads mixture by mixing styrene beads with a boric acid-based inorganic material, producing partially foamed beads by pre-expanding the beads mixture, producing additive-containing beads by adding boric acid-based inorganic materials to the partially foamed beads, and conducting a main expansion treatment to the additive-containing beads. As a result of the above method, coating films containing boric acid-based inorganic materials are formed on the surfaces of the foamed styrene beads, and the coating films increase the fire resistive ability of the Styrofoam product and prevent its thermal contraction and deformation.
A method of producing a Styrofoam product according to another feature of the invention calls for producing a beads mixture by mixing styrene beads with a boric acid-based inorganic material, producing partially foamed beads by pre-expanding the beads mixture, producing additive-containing beads by adding boric acid-based inorganic materials and a thermosetting resin to the partially expanding beads, and conducting a main expansion treatment to the additive-containing beads. As a result of the above method, coating films containing boric acid-based inorganic materials and a thermosetting resin are formed on the surfaces of the formed styrene beads. Therefore, because of synergistic effect between the boric acid-based inorganic materials and the thermosetting resin, the coating films increase the fire resistance of the Styrofoam product and reliably prevent its thermal contraction and deformation.
A method of producing a Styrofoam product according to yet another feature of the invention calls for producing a beads mixture by mixing styrene beads with a boric acid-based inorganic material, producing partially formed beads by pre-forming the beads mixture, producing additive-containing beads by adding a fibrous material, as well as boric acid-based inorganic materials and a thermosetting resin, to the partially formed beads, and conducting a main expansion treatment to the additive-containing beads. As a result of the above method, coating films that contain boric acid-based inorganic materials and a thermosetting resin and are formed on the surfaces of the formed styrene beads increase the fire resistance of the Styrofoam product and reliably prevent its thermal contraction and deformation. Furthermore, the fibrous characteristics of the fibrous material increases the strength of the product.
A method of producing a Styrofoam product according to yet another feature of the invention calls for producing a beads mixture by mixing styrene beads with a boric acid-based inorganic material, producing pre-formed beads by preliminary forming the beads mixture, producing additive-containing beads by adding either one of or both an amino-based resin and a polyamide resin, as well as boric acid-based inorganic materials, a thermosetting resin and a fibrous material, to the pre-formed beads, and conducting a main expansion treatment to the additive-containing beads. As a result of the above method, coating films that contain boric acid-based inorganic materials and a thermosetting resin and are formed on the surfaces of the formed styrene beads increase the fire resistance of the Styrofoam product and reliably prevent its thermal contraction and deformation. Furthermore, the fibrous characteristics of the fibrous material increases the strength of the product, and the amino-based resin and/or the polyamide resin make the product tough.