E.i. Dupont De Nemours and Company

Dupont Safety & Construction, Inc.

Subhotosh Khan

Mikhail R Levit

Gary Lee Hendren

Michael Robert Samuels

Halvar Young Loken

William H Krueger

Wayne F Gentile

John C Chesna

A prepreg composite material that includes a fiber layer and a resin comprising a thermoset resin component, a curing agent and a fibrous micropulp. The micropulp component is an aramid fiber having a volume average length of from 0.01 to 100 micrometers. The prepreg is useful in composite panel construction for minimizing fluid permeation into the cured structure. This prepreg is particularly suitable for making honeycomb sandwich panels. Film adhesives, liquid and paste resins containing aramid fiber micropulp are also disclosed.

Composite panels having improved fluid impermeability

This invention relates to a honeycomb having cells of paper, comprising by weight 3 to 30 parts by weight aliphatic polyamide binder, and 70 to 97 parts of a poly(paraphenylene terephthalamide) fiber having a modulus of 600 grams per denier (550 grams per dtex) or greater, based on the aliphatic polyamide binder and PPD-T fiber in the paper. In another embodiment, the honeycomb is made from paper comprising by weight 30 to 50 parts aliphatic polyamide binder, and 50 to 70 parts of a poly(paraphenylene terephthalamide) fiber having a modulus of 600 grams per denier (550 grams per dtex) or greater, based on the aliphatic polyamide binder and PPD-T fiber in the paper. Both papers have an average specific tensile index of 60 (lbs/in)/opsy (310 Nm/g) or greater. Articles made from the honeycombs include a panel or an aerodynamic structure.

Honeycomb containing poly(paraphenylene terephthalamide) paper with aliphatic polyamide binder and articles made therefrom

Film adhesive of thermoset resin, curing agent and fibrous micropulp

This invention relates to an improved flame retardant honeycomb comprising high modulus fiber and a flame retardant thermoplastic binder having a melt point of from 120&#xb0; C. to 350&#xb0; C. and a limiting oxygen index of 26 or greater, methods for making the honeycomb, and articles comprising the honeycomb. In a preferred embodiment the paper in the honeycomb has a flame classification of UL-94 V-0.

Honeycomb from paper having flame retardant thermoplastic binder

A honeycomb containing a thermoplastic material, high modulus fiber and thermoset resin has process steps of fracturing the thermoset resin, bending, molding or forming the honeycomb in a mold or over a form, heating to allow flow of thermoplastic material and cooling of the honeycomb to retain the shape of the mold or form.

Processes for making shaped honeycomb and honeycombs made thereby

This invention relates to an improved high performance honeycomb, methods for making the same, and articles including aerodynamic structures comprising the honeycomb, the honeycomb made with a paper that allows rapid impregnation of the honeycomb by structural resins while retarding excessive impregnation of node-line adhesives during manufacture. The honeycomb comprises a paper having a thickness of from 25 to 75 microns and a Gurley porosity of 2 seconds or greater and comprising high modulus fiber and thermoplastic binder having a melt point of from 180&#xb0; C. to 300&#xb0; C., wherein at least 30 percent by weight of the total amount of thermoplastic material is in the form of discrete film-like particles in the paper, the particles having a film thickness of about 0.1 to 5 micrometers and a minimum dimension perpendicular to that thickness of at least 30 micrometers.

Honeycomb from controlled porosity paper

This invention relates to a honeycomb including articles such as a panel or aerodynamic structure comprising matrix resin and paper, the paper comprising 50 to 80 parts by weight fibrous material having a modulus of 600 grams per denier (550 grams per dtex) or greater, 0 to 50 parts by weight powdered inorganic material, and 20 parts by weight or greater thermoplastic fiber, the improvement comprising the thermoplastic fiber is a binder for the paper and has a melting temperature above the curing temperature of the matrix resin; a glass transition temperature of greater than 100&#xb0; C., and the weight average molecular weight of the thermoplastic polymer in the thermoplastic fibers changes 20% or less after being maintained for 10 minutes at the melting temperature.

Honeycomb from paper having a high melt point thermoplastic fiber

This invention relates to a honeycomb comprising cells having edges forming a face of the honeycomb, the face defined by a plurality of points and having an area of curvature wherein at least two of the points are located in different tangential planes, the walls of the cells comprising 5 to 50 parts by weight thermoplastic material having a melting point of from 120&#xb0; C. to 350&#xb0; C., and 50 to 95 parts by weight of a high modulus fiber having a modulus of 600 grams per denier (550 grams per dtex) or greater, based on the total amount of thermoplastic material and high modulus fiber in the walls; wherein less than 25 percent of the honeycomb cells in the area of curvature have a re-entrant angle of greater than 180 degrees. This invention also relates to articles including panels and/or aerodynamic structures comprising the honeycomb.

Shaped honeycomb

A sheet comprising thermoplastic polymer (TP) and short high tensile modulus fibers, in which the concentration of TP in the middle of the sheet is higher than at the surface of the sheet, useful for making prepregs with a thermoset resin.

Sheet material especially useful for circuit boards

A process for compression molding a fiber reinforced thermoplastic resin article that includes subjecting the fiber reinforced resin material to heat and pressure to form the article, then directionally cooling the mold sequentially from bottom to top to provide a thermal gradient suitable for creating directional solidification of the material.

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Midlothian, VA, United States of America

Subhotosh Khan