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US 5,346,930 AGranted
Rigid fiberboard
AssigneeLydall, Inc.
InventorsRichard L. Maine, Joseph W. Cook
Life of this patent
Estimating the term…
Abstract
A rigid fiberboard suitable as a replacement for the natural woods presently used for the manufacture of pencils is provided. The fiberboard essentially comprises a fiber network, together with a filler and binder. A lubricant is added to improve the sharpening characteristics of the fiberboard, and dimensional stability is preserved by incorporating a waterproofing agent to minimize the absorption of water by the fiber network.
Claims12
A pencil slat, comprising:
- (A) about 38% to 75% of wet-laid recycled cellulose fibers recovered from recycled materials selected from the group consisting of recycled papers, linters, rags and mixtures thereof;
- (B) about 10% to 30% of organic, particulate filler selected from the group consisting of corn cob flour, corn starch, rice hull flour, nut shell flour, fruit pit flour, wood flour, cork dust and mixtures thereof;
- (C) a sufficient amount of thermosetting binder to provide rigidity to the pencil slat and within the range of about 10% to 35%, said binder being selected from the group consisting of phenolic resins, melamine resins, urea-formaldehyde resins, epoxy resins and mixtures thereof;
- and
- (D) a sufficient amount of lubricating agent to allow a pencil made with said slat to be smoothly sharpened and within the range of about 2% to 15%, said lubricating agent being selected from the group consisting of polyethylene powder, wax, talc, stearates, fatty acids and mixtures thereof.
2 more elements
Dependencies are inferred from the claim text.