Lined plastic closure

Abstract

A plastic closure comprising a base wall and a peripheral skirt. The base wall has an inner surface and a liner is bonded to the inner surface of the base wall of the closure. The liner comprises a fusion blend of a linear ethylene polymer made utilizing single-site catalysts and a lubricant. Preferably the linear ethylene polymer is selected from the group consisting of ethylene-1-octene copolymers and ethylene-1-butene copolymers. The liner is preferably compression molded in the closure. The lubricant comprises an amide, preferably selected from the group consisting of oleamide, erucamide, stearamide, and EBS (ethylene bis stearamide).

Description

This invention relates to plastic closures including liners used especially for hot fill or autoclave applications.

BACKGROUND AND SUMMARY OF THE INVENTION

Conventional liners of EVA or thermoplastic olefins or mixtures thereof usually contain additives such as plasticizers, e.g., mineral oil, which may contribute to contamination of products. Such prior art liners did not offer higher temperature resistances.

In the U.S. Pat. No. 5,306,542 there is disclosed a plastic closure a plastic closure including a base wall having an inner surface, a peripheral skirt extending from the base wall and a liner on the inner surface of the base wall. The liner includes (a) an ethylene vinyl acetate composition, (b) a primary fatty acid amide and (c) a bis-fatty acid amide. Preferably the primary fatty acid amide comprises an oleamide or an erucamide, and the bis-fatty acid amide comprises ethylene-bis-stearamide.

Among the objectives of the present invention are to provide a closure and a liner that can be adhered or preferably compression molded in plastic; and that has specific physical and chemical properties such that the closure and liner can be used for hot fill or autoclaves applications.

In accordance with the invention, the lined plastic closures are capable of withstanding high temperatures which are provided with a liner of a constrained geometry catalyst and polyolefins blended with an amide to provide specific physical and chemical properties, namely, higher temperature resistance, necessary hardness, good process ability.

In accordance with the invention, a plastic closure includes a base wall having an inner surface, a peripheral skirt extending from the base wall and a liner on the inner surface of the base wall.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the invention, a plastic closure includes a base wall having an inner surface, a peripheral skirt extending from the base wall and a liner on the inner surface of the base wall.

The liner comprises a fusion blend of a linear ethylene polymer made utilizing single-site catalysts and a lubricant. Preferably, the linear ethylene polymer is selected from the group consisting of ethylene-l-octene copolymers and ethylene-1-butene copolymers. Linear ethylene polymers of the ethylene-1-octene copolymers are made by Dow Chemical Company and are identified as using DOW INSITE Technology as described in Proceedings of the Second International Business Forum on Specialty Polyolefins SPO '92, Sep. 22-24, 1992, pages 155-165 and in Proceedings of the Third International Business Forum on Specialty Polyolefins SPO '93, Sep. 21-23, 1993, pages 227-245. Ethylene-1-butene copolymers are made by EXXON Chemical Company and are identified as Exxon Exact technology as described in Proceedings of the Third International Business Forum SPO '93, Sep. 21-23, 1993, pages 271-296. Such linear ethylene polymers are sometimes called constrained geometric catalyst polylefins or CGCP resins.

The liner is preferably compression molded.

The lubricant comprises an amide. The lubricant may be selected from the group consisting of oleamide, erucamide, stearamide, and EBS. The lubricant ranges between about 0.25% to 4.5%, by weight, of the liner. When the lubricant comprises oleamide, it is preferably in the range of about 0.25% to 2.0%, by weight, of the liner. When the lubricant comprises erucamide, it is preferably in a range of about 0.25% to 2.0% by weight, of the liner. When the lubricant comprises a mixture of oleamide and erucamide, it is preferably in a total amount of 1.0% by weight, of the liner. When the lubricant comprises a mixture of erucamide and EBS, it is preferably in a total amount of 1%, by weight, of the liner.

The preferred amount of amide used depends on the intended contents of the container which the closure is used. Thus for preferably food and beverage use the amount of 1% ranges between about 0.5% to about 2.0% by weight of the liner. For oil use, the amount of oleamide ranges between about 0.25% and 0.60% by weight of the liner. For bleach use, the amount of oleamide ranges between about 0.5% and 1.5% by weight of the liner.

Tests have been conducted as shown in the following Tables 1-5. Table 1 lists the physical properties of the tested material. The Dow materials are all ethylene-1-octene copolymers made from Dow's INSITE technology. The Exxon materials are all ethylene-1-butene copolymers made from their EXACT technology. Listed are the melt index, hardness, density and crystalline melting points of the virgin materials as received from the vendors.

Table 2 lists all the formulations compounded at OI using the vendor material. Lubricant numbers are utilized to designate the fatty amide lubricant used in the particular formulations. Coefficient of friction at various times is recorded along with the compound hardness.

Table 3 lists the formulation and pack data for the useful formulations, both beverage and food applications. In this Table, the formulations are broken down to their individual components and percent content including all substances that would be entered into the formula from the colorant utilized. The 28 mm beverage closures were applied to the containers with a laboratory filler and capper. The 43 mm Hot Pack (food) closures were packed on PET containers filled with 185.degree. F. water using an OI #59 Series Capper with 5 oz. steam surrounding the closure at application.

Table 4 lists the formulation and data on the most useful non-food compounds. These formulations have been lined into 38 mm closures.

Table 5 lists all the non-food formulations generated along with their hardness and coefficient of friction.

It has been found that for all uses, the melt flow of the materials has to exceed 20 gm/10 min so that pellet bounce during the lining operation is not a problem.

Densities of the useful materials are dependent on the end use. For beverage applications, densities can range between 0.900 g/cc to 0.915 g/cc, this range giving the necessary hardness values of 90-95 Shore A. When utilized for oil applications, materials with a density less than 0.880 g/cc are un-suitable due to the oil dissolving the liner material. Maximum density for oil liner material is 0.900 g/cc. Bleach applications can utilize materials of densities of the minimum available to about 0.880 g/cc.

Coefficient of friction has been determined on 0.005" films using an Altec COF testor. Hardness values are all Shore A. Pack data was derived from closures molded by the compression molding process with the liner formed by compression molding.

It can thus be seen that there has been provided a closure and liner that can be adhered or preferably compression molded in plastic; and that has specific physical and chemical properties such that the closure and liner can be used for hot fill or autoclaves applications.

TABLE 1__________________________________________________________________________CGCT MATERIALS PHYSICAL PROPERTIES MELT HARDNESS DENSITY MELT TEMP VISCMATERIAL INDEX (Shore A) (gm/cc) (.degree. C.) .sup. 1000.sup.-1 P.sub.O2 MOLDING__________________________________________________________________________DOW48562-A32 9.3 95 0.908 103 2256 722 poor48562-A34 4.6 95 0.908 103 306148562-C28 1.3 87 0.885 242148562-C29 1.5 94 0.90248562-C32 2.3 93 0.90348562-14C 17 0.903 1763 poor48562-14D 28 0.902 96 1328 good48562-C45 30 95 0.903 96 goodXU:59002.00 30 95 0.912 105 goodXU:59400.00 30 86 0.88548562-E29 30 74 0.870EXXONExact 3022 9.0 94 0.905 95Exact 4028 10.0 78 0.880Exact 3017 27 85 0.901Exact 4023 35 80 0.880__________________________________________________________________________ *DOW 48562C45 is now numbered XU59100.00 DOW 48562E29 is now numbered XU58320.01 TABLE 2__________________________________________________________________________FOOD AND BEVERAGE FORMULATIONS COFCODE MATERIALS REMARKS LUBE IMMED 1 HOUR 1 DAY HARDNESS__________________________________________________________________________UL-1 Dow A-34 38947NMBD3 oleamide 1.0% 0.045 0.035 0.035 95UL-2 " " oleamide 1.5% 0.045 0.035 0.030 96UL-3 " " oleamide 2.0% 0.035 0.035 0.040 97UL-4 " 38947NMBD1 erucamide 1.0% 0.350 0.040 0.030 97UL-5 " " erucamide 1.5% 0.300 0.040 0.030 98UL-6 " " erucamide 2.0 0.070 0.040 0.035 98UL-7 " 38947NMBD2 EBS 1.0%UL-8 " " EBS 1.5%UL-9 " " EBS 2.0%UL-10 Dow A-32.sup.a,b 38947NMBD3 oleamide 1.0% 0.040 0.035 0.040 94UL-11 " " oleamide 1.5% 0.040 0.040 0.045 96UL-12 " " oleamide 2.0% 0.050 0.035 0.045 96UL-13 " 38947NMBD1 erucamide 1.0% 0.060 0.035 0.035 96UL-14 " " erucamide 1.5% 0.080 0.035 0.035 97UL-15 " " erucamide 2.0% 0.080 0.030 0.035 97UL-16 Dow A-32 lube only oleamide 1.5% 0.110 0.040 0.035 94UL-17 Dow A-34 lube only erucamide 1.5% 0.050 0.040 0.035 96UL-18 Dow A34/Elvax 650 75/25 oleamide 1.0% 0.130 0.040 0.050 95UL-19 Dow A34/Elvax 650 50/50 oleamide 1.0% 0.150 0.045 0.050 95UL-20 " 25/75 oleamide 1.0% 0.150 0.050 0.050 95UL-21 Dow A34/Elvax 450 75/25 oleamide 1.0% >0.40 0.040 0.045 93UL-22 " 50/50 oleamide 1.0% >0.40 0.050 0.045 93UL-23 " 25/75 oleamide 1.0% >0.40 0.050 0.055 92UL-24 Dow A-32 oleamide 0.75% 0.150 0.035 0.040 96UL-25 " oleamide 0.50% >0.40 0.035 0.040 96UL-26 " oleamide 0.25% >0.40 0.035 0.040 96UL-27 " erucamide 0.75% >0.40 0.045 0.040 97UL-28 " erucamide 0.50% >0.40 0.050 0.040 97UL-29 " erucamide 0.25% >0.40 0.065 0.040 96UL-30 Dow A-32 stearamide 1.0% >0.40 >0.40 0.155 96UL-31 " lube 50/50 stear/olea 1.0% 0.080 0.030 0.035 95UL-32 " " stear/eru 1.0% >0.40 0.045 0.038 94UL-33 " " stear/EBS 1.0% >0.40 >0.40 0.185 96UL-34 Dow A-32 lube 50/50 olea/eru 1.0% 0.040 0.035 0.035 96UL-35 " " olea/EBS 1.0% 0.050 0.035 0.032 96UL-36 " " eru/EBS 1.0% 0.100 0.035 0.030 95UL-7 EBS 1.0% >0.40 0.100 0.070 95UL-37 A-32/DP-8310 75/25 oleamide 1.0% >0.40 >0.40 0.055 96UL-38 A-32/DP-8310 50/50 oleamide >0.40 >0.40 >0.40 94UL-39 A-32/DP-8310 25/75 oleamide >0.40 >0.40 >0.40 92UL-40 A-32/butyl 75/25 oleamide 1.0% >0.40 >0.40 0.055 92UL-41 A-32/butyl 50/50 oleamide 1.0% >0.40 >0.40 0.115 83UL-42 A-32/butyl 25/75 oleamide 1.0% -- -- -- --UL-43 A-32(11223-67-1 75/25 oleamide 1.0% >0.40 >0.40 0.035 96UL-44 A-32(11223-67-1 50/50 oleamide 1.0% >0.40 >0.40 0.035 94UL-45 A-32(11223-67-1 25/75 oleamide 1.0% >0.40 >0.40 0.045 94UL-46 C-28 38947NMBD3 oleamide 1.0% >0.40 0.150 0.040 89 0.060@ 24 hrUL-47 C-29 " " 0.060 0.040 0.045 95UL-48 C-32 " " 0.065 0.040 0.035 95UL-49 -14C.sup.a 38947NMBD3 oleamide 1.0% >0.40 0.045 0.040 94UL-50 -14D.sup.a " oleamide 1.0% >0.40 0.030 0.040 94UL-51 -C45 20 MI car 38947NMBD3 oleamide 1.0% 0.150 0.035 0.040 95UL-51A -C45.sup.a,b 50 MI car. 38947NMBE3 oleamide 1.0% >0.400 0.050 0.040 95UL-52 XU:59002.00.sup.a,b oleamide 1.0% 0.060 0.040 0.040 95UL-53 XU:59002.00.sup.a,b 38947NMBD1 erucamide 1.0% >0.400 0.045 0.035 95UL-54 Dowlex 2517 (LLDPE).sup.c 38947NMBD3 oleamide 1.0% 96UL-55 XU59002.00.sup.c 301275NMB erucamide 1.0% >0.400 0.035 0.035 95 Insite carrierUL-56 Exxon 3022 Exact.sup.c 38947NMBD1 erucamide 1.0% >0.400 0.080 0.045 92UL-58 Exxon 3022 Exact oleamide 1.0% 0.090 0.040 0.035 95UL-59 " eru/EBS 1.0% >0.400 0.90 0.070 95UL-60 Dow 59002:00 eru/EBS 1.0% >0.400 0.110 0.100 91UL-61 Exxon 3017 Exact 38947NMBD1 erucamide 1.0% >0.400 0.050 0.045 92__________________________________________________________________________ .sup.a packed under hot pack conditions. .sup.b packed under beverage conditions. 1. all Dow materials are prefixed by the 48562 designation TABLE 3__________________________________________________________________________CGCT PATENT - PACK DATABEVERAGE AND FOODFormulation # UL-10 UL-51A UL-52 UL-53 UL-55__________________________________________________________________________Materialresin (89%) 48562-A32 48562-C45 XU59002 XU59002 XU59002LDPE (10%) 20 melt 50 melt 20 melt 20 melt --XU59002 (10%) -- -- -- -- 30 meltoleamide (1%) 1% 1% 1% --erucamide (1%) -- -- -- 1% 1%BEVERAGEremoval torque(in. lb.)immed 9.2 9.7 10.1 10.9 11.71 day -- 10.9 10.1 11.6 9.51 week 9.2 10.3 9.6 10.6 9.22 week 10.4 10.8 11.1 10.5 8.83 week 11.0 11.1 10.2 9.6 8.14 week 11.1 9.6 10.7 10.4 7.8CO.sub.2 (volume)imm 3.76 3.62 3.56 3.761 day 3.72 3.61 3.78 3.821 week 3.97 3.81 3.65 3.5 3.812 week 4.31 3.68 3.76 3.53 3.663 week 3.73 3.64 3.58 3.63 3.634 week 3.63 3.70 3.64 3.46 3.72HOT PACKremoval torque1 day 20.2 14.0 15.4 15.4 --1 week 16.6 15.3 9.8 12.8 --1 month 16.3 15.0 12.8 11.8 --Leakage none none none none --O.sub.2 permeation 0.060 0.061 0.054 -- -- cc/day cc/day cc/day__________________________________________________________________________ TABLE 4__________________________________________________________________________NON FOOD PATENT DATAFormula- LQ-09 LQ-18tions LQ-02 LQ-06 LQ-07 (Blue) (Black) LQ-11 LQ-12 LQ-13 LQ-14 LQ-15 LQ-19 LQ-20__________________________________________________________________________Resin(89%) Exact XU59400 XU- 1:159400: 1:159400: XU- XU58320.01 XU58320.01 59400/ 59400/ Exact Elvax 250/ 4028 58320.01 58320.01 58320.01 59400 TPO* TPO* 4023 58320.01 25/75 50/50LDPE(10%) 1.0% 1.0% 1.0% 1.0% 1.0% 0.5% 0.5% 0.25% 0.25% 0.5% 0.5% eru 0.5%oleamideHardness 79 86 74 80 80 80 71 73 80 85COF (1 day) 0.080 0.045 0.050 0.050 0.055 >0.400 >0.400Processing poor good good good good good good good good gooduse oil oil oil bleach bleach oil oil oil oil oil bleach bleachPack ResultsOIL CAP28 mm 5.1 3.5 7.1closureremovaltorque(1 wk)adhesion good good good good good good good goodleakage 0% 10% 10% 0% 0% 0% 10% 10%compata- OK dissolved OK OK OK dissolved dissolved OK OK dis- OKbility solvedBLEACH38 mm 13.0 12.5 13.7 13.5closureremovaltorque(1 mo)leakage 0 0 0 0adhesion good good good goodliner decay none none none none__________________________________________________________________________ *Teknor Apex TPO 83F943DNT729 blue Elvax DuPont EVA TABLE 5__________________________________________________________________________(Revised)LQ NON-FOOD FORMULATIONS COFLQ RESIN LUBE immed 4 hr 24 hr HARD__________________________________________________________________________LQ-01 exact 4028 eru 1.0% >0.400 >0.400 >0.400 80LQ-02 " ole 1.0% >0.400 >0.400 0.080 79LQ-03 exact 3017 eru 1.0% >0.400 0.050 0.045 92LQ-04 " ole 1.0% >0.400 0.050 0.040 92LQ-05 adv XU59400.00 eru 1.0% >0.400 >0.400 0.100 86LQ-06 " ole 1.0% >0.400 0.090 0.045 86LQ-07 adv -E29* ole 1.0% >0.400 >0.400 0.050 74LQ-08 adv -E29 eru 1.0% >0.400 >0.400 0.195 74LQ-09 1:1 XU59400.00: ole 1.0% >0.400 0.100 0.050 80 XU58320.01 blueLQ-10 1:1 59400.00/E29 eru 1.0% >0.400 0.250 0.100 79LQ-11 XU59400.00 ole 0.5%LQ-12 XU58320.01 ole 0.5%LQ-13 XU58320.01 ole 0.25%LQ-14 XU59400/TPO** ole 0.25% >0.400 >0.400 >0.400 71LQ-15 XU59400/TPO 50/50 ole 0.50% >0.400 >0.400 >0.400 73 50 meltLQ-16 Elvax 250/TPO 25/75 ole 0.25% >0.400 >0.400 >0.400 71 50 meltLQ-17 Elvax 250/TPO 10/90 ole 0.10% >0.400 >0.400 >0.400 72 Teknor oil TPO >0.400 >0.400 >0.400 71LQ-18 1:1 XU59400.00: ole 1.0% >0.400 >0.400 80 XU58320.01 black***LQ-19 Exact 4023 eru 0.5% 80LQ-20 Elvax 250/58320:01 1:1 eru 0.5%__________________________________________________________________________ *Advantage E29 is XU 58320.01 changed to Engage SM 1200 **TPO is TeknorApex 83F943DNT729 blue oil TPO ***Black Colorant is PMS BN68471NMBE File: Case 16649 LQ Formulation.JWB

Claims

1. A plastic closure for use with containers with hot contents or contents to be autoclaved comprising

a base wall,

a peripheral skirt,

said base wall having an inner surface,

a compression molded liner on said inner surface of said base wall of said closure,

said liner comprising a fusion blend of a linear ethylene polymer made utilizing single-site catalysts and a lubricant,

the amount of lubricant ranging between about 0.25% to 4.5% by weight of the liner,

said fusion blend having a melt flow exceeding 20 gm/10 min to minimize pellet bounce when a pellet is delivered to the base wall,

said liner having a density running between about 0.880 g/cc and about 0.915 g/cc.

2. The plastic closure set forth in claim 1 wherein said lubricant comprises an amide.

3. The plastic closure set forth in claim 2 wherein said lubricant is selected from the group consisting of oleamide, erucamide, stearamide, and EBS (ethylene bis stearamide).

4. The plastic closure set forth in claim 3 wherein said lubricant comprises oleamide and ranges between about 0.25% to 2.0% by weight of the liner.

5. The plastic closure set forth in claim 3 wherein the lubricant comprises erucamide and ranges between about 0.25% to 2.0% by weight of the liner.

6. The plastic closure set forth in claim 3 wherein said lubricant comprises a mixture of oleamide and erucamide and comprises a total amount of about 1.0% by weight of the liner.

7. The plastic closure set forth in claim 3 wherein said lubricant comprises a mixture of erucamide and EBS and comprises a total amount of 1% by weight of the liner.

8. The plastic closure set forth in claim 3 wherein said lubricant comprises an amide and the amount ranges between about 0.5% and about 2% by weight of the liner and the density of the liner ranges between 0.900 and 0.915 g/cc.

9. The plastic closure set forth in claim 3 wherein the lubricant comprises an oleamide and ranges between about 0.25% and 0.60% by weight of the liner and the density of the liner ranges between about 0.880 g/cc and 0.900 g/cc.

10. The plastic closure set forth in claim 3 wherein the lubricant comprises oleamide and ranges between about 0.5% and 1.0% by weight of the liner and the density of the liner is not less than 0.880 g/cc.

11. The plastic closure set forth in any one of claims 1-10 wherein said linear ethylene polymer is selected from the group consisting of ethylene-1-octene copolymers and ethylene-1-butene copolymers.

12. The method of making a plastic closure with a liner comprising

providing a plastic closure having a base wall with an inner surface and a peripheral skirt,

providing a fusion blend of a linear ethylene polymer made utilizing single-site catalysts and a lubricant in an amount ranging between about 0.25% to 4.5% by weight of the fusion blend, said fusion blend having a melt flow exceeding 20 gm/10 min,

severing a pellet from said fusion blend,

delivering said pellet to said inner surface of the base wall such that the melt flow of the fusion blend minimized pellet bounce, and

compression molding said pellet to form a liner having a density range between about 0.880 g/cc and about 0.915 g/cc.

13. The method of making a plastic closure set forth in claim 12 wherein said lubricant comprises an amide.

14. The method of making a plastic closure set forth in claim 13 wherein said lubricant is selected from the group consisting of oleamide, erucamide, stearamide, and EBS (ethylene bis stearamide).

15. The method of making a plastic closure set forth in claim 14 wherein said lubricant comprises oleamide and ranges between about 0.25% to 2.0% by weight of the pellet.

16. The method of making a plastic closure set forth in claim 14 wherein the lubricant comprises erucamide and ranges between about 0.25% to 2% by weight of the pellet.

17. The method of making a plastic closure set forth in claim 4 wherein said lubricant comprises a mixture of oleamide and erucamide and comprises a total amount of about 1.0% by weight of the pellet.

18. The method of making a plastic closure set forth in claim 14 wherein said lubricant comprises a mixture of erucamide and EBS and comprises a total amount of 1% by weight of the pellet.

19. The method of making a plastic closure set forth in claim 14 wherein said lubricant comprises an amide and the amount ranges between about 0.5% and about 2% by weight of the pellet and the density of the liner ranges between 0.900 and 0.915 g/cc.

20. The method of making a plastic closure set forth in claim 14 wherein the lubricant comprises an oleamide and ranges between about 0.25% and 0.60% by weight of the pellet and the density of the liner ranges between about 0.880 g/cc and 0.900 g/cc.

21. The method of making a plastic closure set forth in claim 1 wherein the lubricant comprises oleamide and ranges between about 0.5% and 1.5% by weight of the pellet and the density of the liner is not less than 0.880 g/cc.

22. The method of making a plastic closure set forth in any one of claims 12-21 wherein said linear ethylene polymer is selected from the group consisting of ethylene-1-octene copolymers and ethylene-1-butene copolymers.