# US 8,772,398 B2 · Linerless prepregs, composite articles therefrom, and related methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,772,398 B2 - Document ID: US8772398B2 - Status: Granted - Kind: B2 - Application number: 12/066,263 - Filed: 2006-09-27 - Published: 2008-12-04 - Granted: 2014-07-08 - Earliest claimed: 2005-09-28 - Assignees: Entrotech Composites, LLC - Applicants: Andrew C. Strange; James E. McGuire, Jr. - Inventors: Andrew C. Strange; James E. McGuire, Jr. - Web page: https://patentgrep.com/patent/US8772398B2 ## CPC - C08K 3/36: Silica - C08J 5/248: {using pre-treated fibres} - C08K 3/22: of metals - C08K 7/06: Elements - C08J 2371/00: Characterised by the use of polyethers obtained by reactions forming an ether link in the main chain; Derivatives of such polymers - Y10T 428/31: Surface property or characteristic of web, sheet or block - Y10T 428/31504: Composite [nonstructural laminate] - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Linerless prepreg, composite articles therefrom, and related methods are disclosed. In linerless prepreg according to the invention, matrix material is impregnated into a reinforcement material without the need for any release liners during manufacture or storage thereof. Beneficially, prepreg of the invention is capable of being easily wound into a roll or stacked for storage, without sticking to itself when it is later used in the manufacture of composite articles. ## Claims ### Claim 1 A resin composition forming an initial matrix material during preparation of a composite article, the composition comprising: an essentially uncured initial resin comprising at least one thermosetting resin and, optionally, at least one thermoplastic resin; at least one curative for the at least one thermosetting resin; and at least one viscosity modifier; wherein viscosity of the initial resin in the resin composition is less than about 6 Pa·s when tested at 25° C.; wherein the resin composition is capable of impregnating a reinforcement material to form a prepreg capable of being used to form the composite article without use of release liners; and wherein the resin composition is capable of remaining impregnated throughout the reinforcement material, without partial curing, until final cure of the resin composition to form the composite article. ### Claim 2 (depends on 1) The resin composition of claim 1, wherein the initial resin has a viscosity of about 2.5 Pa·s to about 4.5 Pa·s when tested at 25° C. ### Claim 3 (depends on 1) The resin composition of claim 1, wherein the initial resin comprises at least one resin based on diglycidyl ether of Bisphenol F. ### Claim 4 (depends on 1) The resin composition of claim 1, wherein the reinforcement material comprises a fibrous reinforcement material. ### Claim 5 (depends on 1) The resin composition of claim 1, wherein the viscosity modifier comprises a thixotropic agent. ### Claim 6 (depends on 5) The resin composition of claim 5, wherein the resin composition exhibits Bingham plastic fluid behavior. ### Claim 7 (depends on 1) The resin composition of claim 1, wherein the resin composition exhibits Bingham plastic fluid behavior. ### Claim 8 (depends on 1) The resin composition of claim 1, wherein the viscosity modifier comprises fumed silica. ### Claim 9 (depends on 1) The resin composition of claim 1, wherein the viscosity modifier comprises a nanomaterial. ### Claim 10 (depends on 1) The resin composition of claim 1, wherein about 2% to about 7% by weight of the total resin composition comprises one or more viscosity modifiers. ### Claim 11 (depends on 1) The resin composition of claim 1, wherein the curative facilitates cure of the resin composition within about 45 to about 60 minutes when heated to about 120° C. ### Claim 12 (depends on 1) The resin composition of claim 1, wherein at least one curative is selected from an amine curative and a dicyandiamide. ### Claim 13 (depends on 1) The resin composition of claim 1, further comprising at least one elastomeric toughening component. ### Claim 14 (depends on 1) The resin composition of claim 1, wherein the resin composition is hot-melt processable. ### Claim 15 (depends on 1) A prepreg comprising: the reinforcement material of claim 1; and the resin composition of claim 1 impregnated throughout the reinforcement material. ### Claim 16 (depends on 15) The prepreg of claim 15, wherein the resin composition is essentially uncured. ### Claim 17 (depends on 15) The prepreg of claim 15, wherein the prepreg is manufactured and stored without the use of release liners. ### Claim 18 (depends on 15) A composite article derived from the prepreg of claim 15, wherein the resin composition is cured. ### Claim 19 A linerless prepreg comprising: a reinforcement material; and a matrix material, wherein a layer of the linerless prepreg is capable of being stacked adjacent another layer of the linerless prepreg or rolled upon itself without significantly sticking to the adjacent linerless prepreg layer or itself when used in manufacture of a composite article therefrom. ### Claim 20 A linerless prepreg comprising: a reinforcement material; and a matrix material, wherein a layer of the linerless prepreg is capable of being stacked adjacent another layer of the linerless prepreg or rolled upon itself without significantly sticking to the adjacent linerless prepreg layer or itself when used in manufacture of a composite article therefrom, and, wherein an amount of force required to separate adjacent stacked layers of the linerless prepreg is less than about 3 N/cm as measured according to a 180-degree peel angle test conducted at a testing speed of 30 cm/min (12 in/min). ### Claim 21 (depends on 20) The linerless prepreg of claim 20, wherein the amount of force is less than about 1 N/cm. ### Claim 22 (depends on 1) A method of preparing a prepreg, comprising: providing the resin composition of claim 1; and impregnating the reinforcement material of claim 1 with the resin composition of claim 1 to form the prepreg. ### Claim 23 (depends on 22) The method of claim 22, wherein the resin composition is impregnated throughout the reinforcement material without the use of solvent. ### Claim 24 (depends on 22) The method of claim 22, wherein the resin composition remains essentially uncured until fully curing the prepreg to form a composite article. ### Claim 25 (depends on 15) A method of preparing a composite article, comprising: assembling the prepreg of claim 15 into a desired shape; and curing the resin composition of the prepreg to form the composite article in essentially the desired shape. ### Claim 26 (depends on 1) The resin composition of claim 1, wherein the initial resin consists of thermosettable resin. ### Claim 27 (depends on 1) The resin composition of claim 1, wherein thermosettable resin in the initial matrix material consists of the initial resin having a viscosity of less than about 6 Pa·s when tested at 25° C.