US3748297A - Polychloroprene gasket-forming compositions containing as a rheologyaffecting additive, 2-mercaptobenzothiazole - Google Patents

Polychloroprene gasket-forming compositions containing as a rheologyaffecting additive, 2-mercaptobenzothiazole Download PDF

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Publication number
US3748297A
US3748297A US00137638A US3748297DA US3748297A US 3748297 A US3748297 A US 3748297A US 00137638 A US00137638 A US 00137638A US 3748297D A US3748297D A US 3748297DA US 3748297 A US3748297 A US 3748297A
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United States
Prior art keywords
mercaptobenzothiazole
gasket
polychloroprene
compounds
parts
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Expired - Lifetime
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US00137638A
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English (en)
Inventor
J Gribens
A Giannetto
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WR Grace and Co Conn
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WR Grace and Co
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Assigned to W. R. GRACE & CO.-CONN. reassignment W. R. GRACE & CO.-CONN. MERGER (SEE DOCUMENT FOR DETAILS). Assignors: GRACE MERGER CORP. A CT CORP. (MERGED INTO), W. R. GRACE & CO. A CT. CORP.
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Expired - Lifetime legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16JPISTONS; CYLINDERS; SEALINGS
    • F16J15/00Sealings
    • F16J15/02Sealings between relatively-stationary surfaces
    • F16J15/14Sealings between relatively-stationary surfaces by means of granular or plastic material, or fluid
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00Use of organic ingredients
    • C08K5/36Sulfur-, selenium-, or tellurium-containing compounds
    • C08K5/45Heterocyclic compounds having sulfur in the ring
    • C08K5/46Heterocyclic compounds having sulfur in the ring with oxygen or nitrogen in the ring
    • C08K5/47Thiazoles
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K3/00Materials not provided for elsewhere
    • C09K3/10Materials in mouldable or extrudable form for sealing or packing joints or covers
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2200/00Chemical nature of materials in mouldable or extrudable form for sealing or packing joints or covers
    • C09K2200/02Inorganic compounds
    • C09K2200/0239Oxides, hydroxides, carbonates
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2200/00Chemical nature of materials in mouldable or extrudable form for sealing or packing joints or covers
    • C09K2200/02Inorganic compounds
    • C09K2200/0243Silica-rich compounds, e.g. silicates, cement, glass
    • C09K2200/0252Clays
    • C09K2200/026Kaolin
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2200/00Chemical nature of materials in mouldable or extrudable form for sealing or packing joints or covers
    • C09K2200/04Non-macromolecular organic compounds
    • C09K2200/0488Sulfur-containing compounds
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2200/00Chemical nature of materials in mouldable or extrudable form for sealing or packing joints or covers
    • C09K2200/06Macromolecular organic compounds, e.g. prepolymers
    • C09K2200/0607Rubber or rubber derivatives

Definitions

  • a typical aerosol unit is composed of a hollow cylindrical container closed at one endand provided with an opening at its opposite end for receiving a dispensing valve assembly.
  • a metal mounting cup serves as a 010- sure for the container and also as a support for the valve assembly which is tightly fitted within an aperture centrally located in the cup.
  • the mounting cup carries an annular gasket adapted at its outer edge to be crimped to the walls forming the opening in the container and thereby form a seal upon crimping.
  • the gasketing material used in aerosol mounting cups must be elastic and resilient. It must be capable of yielding under deforming forces to establish a satisfactory seal when the cup is crimped to the container. It must also be capable of maintaining the seal during normal storage periods. Often selected for this function are gaskets prepared from solvent-based rubber compositions which comprise an elastomer dissolved in a volatile organic solvent. The compositions may also contain pigments, fillers, curing agents and other conventional compounding ingredients. Because of superior resistance to oxidation and to oils and propellants as well as to various other chemicals commonly found in aerosol containers, neoprene (a chlorobutadiene polymer) has become the favored elastomer in this type of composition.
  • a band of the fluid composition is deposited in the annular channel of the mounting cup while the cup is being rotated beneath a metering nozzle through which the composition flows to form a continuous annular deposit. This deposit is subsequently converted into a dry solid elastomeric sealing mass by expulsion of the solvent and cured at elevated temperatures.
  • compositions that can benefit from the present invention consist essentially of a polymer of 2-chloro-1,3- butadiene dissolved in a volatile organic solvent.
  • the elastomeric polymer may be either a homopolymer of the chloroprene or a copolymer containing minor quantities of styrene, acrylonitrile, isoprene and other monomeric units copolymerizable with it.
  • chloroprene polymers are commonly referred to as neoprenes and are commerically available as general-purpose types, such as GN, GNA, GRT, W, WRT and WHV. Any general purpose neoprene may be used alone or in admixture.
  • special purpose neoprenes such as KNR, CG and AC, may be used in combination with general-purpose types.
  • the chloroprene polymer may be dissolved in a single volatile organic liquid or in mixture of such liquids able to function together as solvent medium.
  • Preferred usable organic liquids in this capacity are those that have a minimum boiling point of 230 F., as well as mixtures of liquids that do not boil below 230 F. and yet are capable of volatilization in the course of the overall drying and curing cycle to which the gasketing compounds are subjected.
  • Illustrative of this type of liquids are toluene, xylene, a high boiling petroleum solvent such as Solvesso wtih a boiling range of 230 F. to 345 R, an aliphatic petroleum solvent such as Varsol #1 which boils between 320 F. and 390 F., and mixtures of such liquids.
  • the volatile Organic liquid selected is used in quantities such that compositions having a total solids concentration between about 40 and 50% by weight, and preferably between about 45 and 50% by weight, are obtained.
  • the total solids portion of the compositions includes the combined weight of polymer, fillers, curing mixture and the other substantially non-volatile ingredients employed.
  • the amount of the polymer in the composition should be at least about 21% of the weight of the total composition.
  • the curing agent may be a metallic oxide such as magnesium oxide, zinc oxide, a lead oxide, or mixtures of elemental sulfur with a metallic oxide. About 1 to 15 phr. of curing agent is generally used, any excess over that level acting as filler. Preferably, a mixture of oxides is used that contains about 4 phr. of a light or extra light calcined magnesia per 5 phr. of zinc oxide, such a mixture providing relatively rapid and complete cure with minimum scorching.
  • a curing accelerator may be used in conjunction with the oxides, e.g. Z-mercaptoimidazoline or p,p'-diaminodiphenylmethane.
  • compositions may include a non-volatile liquid plasticizer in quantities ranging between about 0 and 20 phr.
  • plasticizers facilitate mixing of the polymer with other ingredients such as fillers and also enhance the sealing characteristics of the resulting gasket.
  • the plasticizer is used at a level not greater than phr.
  • Illustrative plasticizers include dioctyl sebacate, dioctyl adipate, didecyl phthalate, dioctyl phthalate, naphthenic oils or any relatively non-volatile liquid plasticizing material conventionally used as processing aid for neoprene rubber.
  • inorganic fillers While the presence of inorganic fillers is not essential in the present compositions, their use in sealing aerosol containers tends to reduce the permeability of the gasket to propellants. Fillers are also helpful in modifying the specific gravity and flow characteristics of the fluid com position. Suitable fillers include hydrated calcium silicate, fine sized Whiting, talc, silicon dioxide and clays. The quantity of filler may range between about 0 and 100 phr. Quantities ranging between about 30 and 70 phr. are preferred, the exact quantity used depending upon the filler or combination of fillers selected, the characteristics imparted to the fluid composition, and the properties desired in the cured gasket.
  • Peptizers allow greater ease in adjusting the viscosity of the composition to a value within the range required for standard lining equipment.
  • Typical eptizers include alkyl thiuram disulfides, e.g. tetramethyl and tetraethyl thiuram disul fides; piperidinium alkyl dithiocarbamates, e.g. piperidiniumpentamethylene dithiocarbamate; and guanidines.
  • Peptizers are used in quantities preferably between about 0.5 and 6 phr.
  • lubricants e.g. stearic acid and petroleum waxes
  • antioxidants e.g. diphenyl-p-phenylenediamine and p-(p-tolylsulfonylamide)diphenylamine
  • pigments e.g. carbon black, iron oxide and titanium dioxide.
  • Example- 3 4 5 6 Fixed Ingredients (parts by weight):
  • Polychloroprene (Neoprene GN)- 100 100 100 Paraflin wax 2.0 2.0 2.0 2. 0 Sodium acetate 1. 5 1. 5 1. 5 1. 5 Magnesium oxide 8. 0 8. 0 8. 0 8. 0 Tetraethylthiuram disulfide- 2. 5 2. 5 2. 5 2. 6 Piperidinium-pentamethylene dithiocarbarnat-e 2. 0 2. O 2. 0 2. 0 Zinc oxide 5. 0 5. 0 5. 0 5. 0 5. 0 Dioetyl 7. 4 7. 4 7. 4 7. 4 7. 4 Silica ge 0.1 0. 1 0. 1 0.1 Ziuce resinate O. 3 0. 3 0. 3 0. 3 Xylene 200 200 200 200 Variable ingredients (parts by weight):
  • 2-mercaptobenzothiazole 2 2 Aluminum silicate (kaolin) 50 60 Calcium carbonate I 50 50 A Darex #9 ACF automatic compound lining machine for aerosol mounting cups was used in these tests. The machine was adjusted so that the compound of Example 5 was lined with lap bubbles. Then, without disturbing the lap setting of the machine, the compounds of Example 3, 6 and 4 were lined in that order. Approximately 300 cups were lined with each of the four compounds. The only variance used in lining each compound was the pressure used to regulate the quantity of material. This is necessary to achieve a substantially constant quantity of cured compound among all compounds. Enough of each compound was thus applied to give gaskets of 0.023 inch in thickness having the following film Weights: 605 mg., 625 mg., 625 mg. and 630 mg. for the compounds of Examples, 3, 4, 5 and 6 respectively. After lining, the compounds were put through a normal aerosol gasket curing cycle of 1 hour air drying, 1 hour heating at F., 1 hour at 250 F. and 1 hour at 325 F.
  • a composition for forming flowed-in gaskets comprising, on a weight basis, 100 parts of a polymer of 2- chloro l,2-butadiene, between 0.5 and 6 parts of a peptizer, between 1 and 15 parts of a curing agent, between 0 and 20 parts of a non-volatile plasticizer for the polymer, between 0 and 100 parts of a filler, between 1.25 and 4 parts of Z-mercaptobenzothiazole, and sufficient volatile liquid hydrocarbon solvent, having a minimum boiling References Cited UNITED STATES PATENTS 3,389,113 6/1968 Simons et a1 26041.5 R 3,310,524 3/1967 Hurlock et a1. 26045.8 SN 3,220,968 11/1965 Dollhausen et a1. 2603 1.8 DR 2,802,811 8/1957 Somerville et a1. 26045.8 SN

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Sealing Material Composition (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
US00137638A 1971-04-26 1971-04-26 Polychloroprene gasket-forming compositions containing as a rheologyaffecting additive, 2-mercaptobenzothiazole Expired - Lifetime US3748297A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US13763871A 1971-04-26 1971-04-26

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US3748297A true US3748297A (en) 1973-07-24

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US00137638A Expired - Lifetime US3748297A (en) 1971-04-26 1971-04-26 Polychloroprene gasket-forming compositions containing as a rheologyaffecting additive, 2-mercaptobenzothiazole

Country Status (7)

Country Link
US (1) US3748297A (https=)
AU (1) AU4156272A (https=)
CA (1) CA966945A (https=)
DE (1) DE2220174A1 (https=)
FR (1) FR2136716A5 (https=)
IT (1) IT956232B (https=)
ZA (1) ZA722803B (https=)

Also Published As

Publication number Publication date
IT956232B (it) 1973-10-10
FR2136716A5 (https=) 1972-12-22
ZA722803B (en) 1973-02-28
AU4156272A (en) 1973-11-01
CA966945A (en) 1975-04-29
DE2220174A1 (de) 1972-11-09

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AS Assignment

Owner name: W. R. GRACE & CO.-CONN., MASSACHUSETTS

Free format text: MERGER;ASSIGNORS:GRACE MERGER CORP. A CT CORP. (MERGED INTO);W. R. GRACE & CO. A CT. CORP.;REEL/FRAME:005206/0001

Effective date: 19880525