# US 11,111,422 B2 · Hydraulic fluid and fuel resistant sealants

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- Number: US 11,111,422 B2
- Document ID: US11111422B2
- Status: Granted
- Kind: B2
- Application number: 16/782,137
- Filed: 2020-02-05
- Published: 2020-06-04
- Granted: 2021-09-07
- Earliest claimed: 2017-07-07
- Assignees: PRC-DeSoto International, Inc.
- Applicants: PRC—DeSoto International, Inc.
- Inventors: Renhe Lin; Weibin Cui
- Web page: https://patentgrep.com/patent/US11111422B2

## CPC

- C09J 163/04: Epoxynovolacs
- C08L 81/02: Polythioethers; Polythioether-ethers
- C09J 163/00: Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
- C09K 3/1012: {Sulfur-containing polymers, e.g. polysulfides}
- C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

Compositions that are resistant to hydraulic fluid and aviation fuel contain sulfur-containing prepolymers and solvent-resistant organic fillers. The compositions are useful in aerospace sealant applications.

## Claims

### Claim 1

A composition comprising:
(a) from 35 wt % to 65 wt % of a thiol-terminated sulfur-containing prepolymer;
(b) from 10 wt % to 35 wt % of an organic filler;
(c) from 5 wt % to 30 wt % of an inorganic filler; and
(d) from 5 wt % to 20 wt % of a polyepoxide,
wherein the composition has a specific gravity less than 1.2, wherein specific gravity is determined according to ISO 2781; and
wherein wt % is based on the total weight of the composition.

### Claim 2 (depends on 1)

The composition of claim 1, wherein the organic filler has a specific gravity less than 1.6 as determined according to ISO787 (Part 10).

### Claim 3 (depends on 1)

The composition of claim 1, wherein the organic filler exhibits less than 1 vol % swelling following immersion in aviation hydraulic fluid at a temperature of less than 50° C. for 1,000 hours, wherein percent swelling is determined according to EN ISO 10563.

### Claim 4 (depends on 1)

The composition of claim 1, wherein the organic filler has a specific gravity from 0.85 to 1.4, wherein specific gravity is determined according to ISO 787 (Part 10).

### Claim 5 (depends on 1)

The composition of claim 1, wherein the organic filler comprises solid particles.

### Claim 6 (depends on 1)

The composition of claim 1, wherein the organic filler comprises a polyamide, a polyimide, a polyphenylene sulfide, a polyether sulfone, a thermoplastic copolyester, or a combination of any of the foregoing.

### Claim 7 (depends on 1)

The composition of claim 1, wherein the organic filler further comprises expanded thermoplastic microcapsules coated with a melamine resin.

### Claim 8 (depends on 1)

The composition of claim 1, wherein the thiol-terminated sulfur-containing prepolymer comprises a thiol-terminated polythioether prepolymer, a thiol-terminated polysulfide prepolymer, a thiol-terminated sulfur-containing polyformal prepolymer, a thiol-terminated monosulfide prepolymer, or a combination of any of the foregoing.

### Claim 9 (depends on 1)

The composition of claim 1, wherein the thiol-terminated sulfur-containing prepolymer comprises a thiol-terminated polythioether prepolymer comprising at least one moiety having the structure of Formula (1):
R1[S—(CH2)2—O—(R2—O—)m(CH2)2—S—R1]n−ti—(1)
wherein,
each R1 is independently selected from a C2-10 n-alkanediyl group, a C3-6 branched alkanediyl group, a C6-8 cycloalkanediyl group, a C6-10 alkanecycloalkanediyl group, a divalent heterocyclic group, and a —[(CHR3)p—X—]q(CHR3)r—group, wherein each R3 is selected from hydrogen and methyl;
each R2 is independently selected from a C2-10 n-alkanediyl group, a C3-6 branched alkanediyl group, a C6-8 cycloalkanediyl group, a C6-14 alkanecycloalkanediyl group, a divalent heterocyclic group, and a —[(CH2)p—X—]q(CH2)r—group;
each X is independently selected from O, S, and NR, wherein R is selected from hydrogen and methyl;
m ranges from 0 to 50;
n is an integer ranging from 1 to 60;
p is an integer ranging from 2 to 6;
q is an integer ranging from 1 to 5; and
r is an integer ranging from 2 to 10.

### Claim 10 (depends on 1)

The composition of claim 1, wherein the thiol-terminated sulfur-containing prepolymer comprises a thiol-terminated polythioether prepolymer of Formula (1a), a thiol-terminated polythioether prepolymer of Formula (1b), a thiol-terminated polythioether prepolymer of Formula (1c), or a combination of any of the foregoing:
HS—R1—[S—(CH2)2—O—(R2—O)m(CH2)2—S—R1—]nSH (1a)
{HS—R1—[S—(CH2)2—O—(R2—O)m(CH2)2—S—R1—]nS—V′—}zB (1b)
{R4—S—R1—[S—(CH2)2—O—(R2—O—)m(CH2)2—S—R1]nS—V′—}zB (1c)
wherein,
each R1 is independently selected from C2-10 alkanediyl, C6-8 cycloalkanediyl, C6-14 alkanecycloalkanediyl, C5-8 heterocycloalkanediyl, and —[(CHR3)p—X—]q(CHR3)r 13,
wherein,
p is an integer from 2 to 6;
q is an integer from 1 to 5;
r is an integer from 2 to 10;
each R3 is independently selected from hydrogen and methyl; and
each X is independently selected from —O—, —S—, and —NR—, wherein R is selected from hydrogen and methyl;
each R2 is independently selected from C1-10 alkanediyl, C6-8 cycloalkanediyl, C6-14 alkanecycloalkanediyl, and —[(CHR3)p—X—]q(CHR3)r—, wherein p, q, r, R3, and X are as defined as for R1;
m is an integer from 0 to 50;
n is an integer from 1 to 60;
B represents a core derived from a z-valent, polyfunctionalizing agent B(—V)z wherein,
z is an integer from 3 to 6; and
each V is a moiety comprising a terminal group reactive with a thiol;
each —V′— is derived from the reaction of —V with a thiol;
each R4 is independently selected from hydrogen and a bond to the polyfunctionalizing agent B(—V)z, through a moiety of Formula (1).

### Claim 11 (depends on 1)

The composition of claim 1, wherein the inorganic filler comprises precipitated calcium carbonate, fumed silica, or a combination thereof.

### Claim 12 (depends on 1)

The composition of claim 1, wherein the polyepoxide comprises a hydroxyl-functional bisphenol A/epichlorohydrin derived polyepoxide, a phenol novolac polyepoxide, or a combination thereof.

### Claim 13 (depends on 1)

The composition of claim 1, wherein the polyepoxide comprises from 30 wt % to 80 wt % of a hydroxyl-functional polyepoxide; wherein wt % is based on the total weight of the polyepoxide in the composition.

### Claim 14 (depends on 1)

The composition of claim 1, comprising an adhesion promoter, wherein the composition comprises from 0.5 wt % to 4 wt % of the adhesion promoter; and wt % is based on the total weight of the composition.

### Claim 15 (depends on 1)

The composition of claim 1, comprising an adhesion promoter, wherein the adhesion promoter comprises an organo-functional silane, a phenolic resin, or a combination thereof.

### Claim 16 (depends on 1)

The composition of claim 1, wherein the composition comprises a specific gravity within a range from 0.9 to 1.15, wherein the specific gravity is determined according to ISO 2781.

### Claim 17 (depends on 1)

The composition of claim 1, wherein,
the thiol-terminated sulfur-containing prepolymer comprises a thiol-terminated polythioether prepolymer;
the organic filler further comprises expanded thermoplastic microcapsules coated with a melamine resin;
the inorganic filler comprises precipitated calcium carbonate and fumed silica; and
the polyepoxide comprises a hydroxyl-functional bisphenol A/epichlorohydrin derived polyepoxide and a phenol novolac polyepoxide.

### Claim 18 (depends on 1)

A cured composition obtained from the composition of claim 1.

### Claim 19 (depends on 18)

The cured composition of claim 18, wherein the cured composition comprises a tensile strength greater than 1 MPa, an elongation greater than 150%, and a hardness greater than Shore 30A, following immersion in hydraulic fluid at 70° C. for 1,000 hours, wherein, tensile strength is determined according to ISO 37, elongation is determined according to ISO 37, and hardness is determined according to ISO 868.

### Claim 20 (depends on 18)

A part comprising the cured composition of claim 18.

### Claim 21 (depends on 18)

A vehicle comprising the cured composition of claim 18.

### Claim 22 (depends on 21)

The vehicle of claim 21, wherein the vehicle comprises an aerospace vehicle.

### Claim 23

A sealant system comprising a first part and a second part, wherein,
the first part comprises:
from 50 wt % to 70 wt % of a thiol-terminated sulfur-containing prepolymer;
from 15 wt % to 40 wt % of an organic filler;
from 2 wt % to 16 wt % of an inorganic filler, and
from 0.5 wt % to 3 wt % of an adhesion promoter,
wherein wt % is based on the total weight of the first part; and
the second part comprises:
from 35 wt % to 80 wt % of a polyepoxide;
from 10 wt % to 50 wt % of an inorganic filler, and
from 0.5 wt % to 10 wt % of an adhesion promoter,
wherein wt % is based on the total weight of the second part,
wherein the combined first part and the second part has a specific gravity less than 1.2, wherein specific gravity is determined according to ISO 2781.

### Claim 24 (depends on 23)

A cured composition prepared from the sealant system of claim 23.

### Claim 25 (depends on 24)

A part sealed with the cured composition of claim 24.

### Claim 26 (depends on 24)

A vehicle comprising the cured composition of claim 24.

### Claim 27 (depends on 26)

The vehicle of claim 26, wherein the vehicle comprises an aerospace vehicle.

### Claim 28 (depends on 1)

A method of sealing a part, comprising:
applying the composition of claim 1 to a part; and
curing the applied composition to provide a sealed part.

### Claim 29 (depends on 23)

A method of sealing a part, comprising:
combining the first part of the sealant system of claim 23 with the second part of the sealant system of claim 23 to provide a sealant composition;
applying the sealant composition to a part; and
curing the applied sealant composition to provide a sealed part.

### Claim 30 (depends on 1)

The composition of claim 1, wherein the organic filler further comprises expanded thermoplastic microcapsules coated with a urea/formaldehyde resin.

### Claim 31 (depends on 1)

The composition of claim 1, wherein,
the thiol-terminated sulfur-containing prepolymer comprises a thiol-terminated polythioether prepolymer;
the organic filler further comprises expanded thermoplastic microcapsules coated with a urea/formaldehyde resin;
the inorganic filler comprises precipitated calcium carbonate and fumed silica; and
the polyepoxide comprises a hydroxyl-functional bisphenol A/epichlorohydrin derived polyepoxide and a phenol novolac polyepoxide.

### Claim 32 (depends on 23)

The composition of claim 23, wherein the organic filler further comprises expanded thermoplastic microcapsules coated with a urea/formaldehyde resin.

### Claim 33 (depends on 23)

The composition of claim 23, wherein,
the thiol-terminated sulfur-containing prepolymer comprises a thiol-terminated polythioether prepolymer;
the organic filler further comprises expanded thermoplastic microcapsules coated with a urea/formaldehyde resin;
the inorganic filler comprises precipitated calcium carbonate and fumed silica; and
the polyepoxide comprises a hydroxyl-functional bisphenol A/epichlorohydrin derived polyepoxide and a phenol novolac polyepoxide.