FR2825131A1 - PVC COMPOSITIONS FOR REFRIGERANT DOOR GASKET - Google Patents

Abstract

PVC composition for refrigerating appliance door seal comprising from 0.01 to 1.0% by weight of at least one biocide taken from a list comprising methyl-2-benzimidazole carbamate, 2- (4-triazolyl ) -benzimidazole, alpha- [2- (4-chlorophenyl) -ethyl] -alpha- (1, 1-dimethylethyl) -1H-1, 2, 4-triazol-1-ethanol and zinc bis (2-pyridilthio -1-oxide), relative to the weight of PVC.

Description

rotation of said pinion (70).

  PVC COMPOSITIONS FOR DOOR SEAL

OF REFRIGERATOR

  The present invention relates to a polyvinyl chloride (PVC) composition for a refrigerating appliance door seal and a method for manufacturing a refrigerating appliance door seal using this composition, and more particularly, to a PVC composition for a refrigerant door seal. refrigerating appliance and a method of manufacturing a door seal for a refrigerating appliance using the composition which prevents the formation of molds or bacteria which migrate from the plasticizer by adding a certain biocide to

the composition of PVC.

  The conventional PVC composition for refrigerant door seal contains PVC, a plasticizer, heat, cold and weather resistant stabilizers, a filler and a pigment. A seal is made by mixing, composition and extrusion. As PVC is in powder form, a plasticizer is used to make the PVC smooth and thus facilitate the manufacturing process. However, a PVC door seal for a refrigerating appliance, manufactured according to the process mentioned above, undergoes a migration phenomenon which causes the plasticizer to flow outside the seal between 60 and 80 C. In addition, at a temperature above 100 C, the plasticizer escapes in a proportion of more than 1 to 2% of the total weight of the PVC joint. Consequently, parts of the surfaces in contact with ABS or HIPS, which are materials for the internal surface of the refrigerating appliance, are easily contaminated and there follows a problem of partial discoloration with the appearance of s yellow or blue stains or even in red since there are sufficient spaces on the surface of the joint where the

  mold and bacteria can spread.

  In order to prevent the spread of bacteria, Korean Patent No. 10-1993-023682 and Publication No. 10-1995-006264 disclosed the use of a mold protecting substance to which 10, 10'- is added. oxybisphenoxagene (Hokustar-HP product name from Gitagooga materials of Japan). However

  the effect of this substance has been shown to be insufficient.

  Accordingly, the object of the present invention is to provide a PVC composition for refrigerant door seal and a method of manufacturing refrigerant door seal using this composition which prevents contamination and discoloration due to spread of mold or bacteria on the surface of the joint thanks to the addition

of a certain PVC biocide.

  To accomplish this and to benefit from other 2s advantages, in accordance with the aim of the present invention, as it is written and abundantly described here, PVC compositions for refrigerant door gasket containing at least one selected biocide are proposed. from a list consisting of methyl-2-benzimidazole carbamate, 2- (4triazolyl) -benzimidazole, c- [2- (4-chlorophenyl) -ethyl] - (1,1dimethylethyl) -lH

  1,2,4-triazol-1-ethanol and zinc bis (2-pyridilthio-1-

  oxide) in a proportion of between 0.01 and 1.0% by

  weight of biocide relative to the weight of PVC.

  The foregoing, like other objects, objects, aspects and advantages of the present invention will be

  clarified in the following detailed description of the

  present invention, which must be considered in conjunction

  with the accompanying drawings.

  Reference is now made in detail to the preferred real i sat ions of the present invention.

  examples of which are illustrated in the associated drawings.

  According to the present invention, a polyvinyl chloride having a degree of polymerization of about 1300

can be used.

  The biocides used in the present invention prevent contamination and discoloration by molds or bacteria which appear with the migration of a plasticizer. The following biocides are

  used in the present invention.

  Methyl-2-benzimidazole cartamate (common name: carbendazime)

ÉHCO083

  H 2- (4-triazolyl) -beuzimidazole (common name: TBZ) / H N -; a- [2- (4chlorophenyl) -ethyl] -G- (1,1-dimethylethyl) -1H 1,2,4-triazol-1-ethanol (common name: tebukonazol) Cl_> 'N; N Zinc bis (2-pyridilthio-1-oxide) (common name: zinc pyrition) S 1 n! O 2 As a biocide, one can use a single chemical compound or mix two or more types of biocides. According to the present invention, the biocide can achieve higher efficiency by mixing two or more chemical compounds. The amount of biocide to be used is from 0.001 to 1.0% by weight of biocide relative to the weight of PVC. If the quantity is less than 0.001% by weight of biocide, the effect of the biocide is not significant and if it is greater than l of the weight of biocide, no effect

  additional cannot be obtained.

  In the PVC composition according to the present invention, other common additives can be added. A plasticizer can be added to make the extraction and compression transformation process simpler by causing a flow of plastic giving fluidity to the PVC macromolecule and to increase flexibility by reducing the hardness of the polymer. As far as the plasticizer is concerned, diocLyl phthalate (DOP), dioctyl adiphate (DOA), diisodecyl phLalate (DIP) and triocLyl trimelitate (TOTM) are used and a proportion of 30 to 80% or preferably is used. from 50 to 70% by weight of plasticizer relative to the weight

PVC.

  In addition, a stabilizer can be added to stabilize the polymer against heat, oxygen and ultraviolet rays during the process or in use. The term "stabilizer" is intended to mean in particular a heat-resistant stabilizer such as barium stearate, calcium stearate and epoxy bean oil, a cold-resistant stabilizer such as the butyltin laurate complex and a weather resistant stabilizer such as the organic phosphite ester complex. 1 to 5% by weight of

  stabilizer in relation to the weight of PVC.

  A filler can be added to improve mechanical intensity, format stability, temperature change state due to heat, hardness and other physical characteristics. For the present invention, CaCO3 is preferably used as a filler and is added in an amount of 5 to 50% and preferably 10 to 30 by weight of CaCO3 relative to the weight of PVC. In addition, a pigment can be added to obtain a good color in the proportion of 0.001 to 1% by weight of pigment relative to the weight of PVC. For example, the pigment may include titanium oxide,

carbon or purple.

  In an example of manufacture of PVC according to the present invention, a Henschal mixer can be used in a conventional manner. The PVC, the possible additives and the pigments, as described above, are added to the mixture, the temperature of the mixer being maintained between 60 and 120 ° C., and they are stirred for 1 to 2 minutes at low speed of Orpm. A plasticizer is introduced into the mixture at a temperature of 50 to 100 ° C. and it is stirred at low speed, or alternately at low and at high speed,

  and preferably at low speed.

  Then, a filling material is added and brought (formulated) to the temperature of 105 to 100 C. The resulting composition (formulation) is poured out and transferred to a cooling mixer. The composition is cooled to a temperature below C and a resulting product in the form of powder is obtained. Powder products are transferred

  to an extractor and are extracted.

  Next, the present invention will be described

with reference to the examples.

  The temperature of the oil jacket S of a Henschal 200L mixer was maintained at 80 C, the PVC having a degree of polymerization of 1300 and the other additives were introduced into the mixture as indicated on the Table 1. The PVC mixture was stirred at the low speed of 40 rpm for 2 minutes. Then, 1 kg of plasticizer was added every minute through a plasticizer heat riser and stirred at the speed of 500 rpm. A filling material based on calcium carbonate (CaC03) is added to the above resulting mixture, brought (formulated) 1S to 110 C. The composition (formulation) was poured out

   C and transferred to a cooling mixer.

  Then the resuItant composition was cooled to a temperature below 40 C and the product was obtained in the form of powder. The powder products were extruded to make a seal.

Table 1

  Components Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 PVC (kg) 100 100 100 100 100 100 DOP (kg) 60 60 60 60 60 60 DOA (kg) 4. 6 5 6 4 7.5 TOTM (kg) 6 2 2.5 Bean oil 1 1 1 1 1 1 epoxidized (epoxyed

bean oil) (kg).

  BP-203S (kg) 1.6 1.6 1.6 1.6 1.6 1.6 Stearic acid 1.6 1.6 1.6 1.6 1. 6 1.6 (kg) -. BZ-108 (kg) _ Ca CO3 (kg) 20 20 20 20 20 20 Carbendazime 0.05 0.05 0.05 _ (kg). TBZ (kg) 0.05 0.05 0.05 _ Tebukonazol (kg) 0.05 0.05 0.05 Zinc-pyridion _. 0.05 0.05 0.05 (kg) Ti O2 (kg) 2 2 2 2 2 2 Carbon black 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 (kg) H-blue (-blue) 0.024 0.024 0024 0.024 0.024 0.024 (kg) Violet (kg) 0.1 0.1 0.1 0.1 0.1 0.1 s The result of a characteristic measurement of the products obtained in the above examples is described

in table 2.

Table 2

  Characteristics Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Shoa hardness A 70 72 69 70 71 70 Recurrence at 1.49 0.92 0. 97 1.05 1.39 1.28 traction (kg / mm) Percentage 235 219 211 224 229 231% elongation (200) Weight loss per 3.12 2.58 3.10 2.87 2.64 2.46 heat (). Adhesion strength - 3. as 3.24 4.12 3.68 3.14 4.19 Ray resistance 0.54 0.45 0.12 0.48 0.41 0.29 ultraviolet (EO) Chemical resistance O Erosion by OO contaminatlon Discoloration H2S OOOOOO Test on bottle 94.47 92.63 91.31 90.79 90.57 91.35 stirring Decrease rate of the number of viable cells Halo test ** 3 {growths 3 [growth 3 (growth 3 [growth 3 (growth 3 icro iseance Resistance to mycelia non mycelian non mycelian non mYcelian non mycelian non mycelian not recognized) recognizable) ) recognizable) recognizable) recognizable) distortion. Inhibition ring (mm) 6 8 6 6 8 8 * resistance test against bacteria: name of bacilli of the colon E-Coli (ATCC 25922) ** resistance test against mold: ASRM G-21 The result of the examples shows that a PVC composition according to the present invention has excellent characteristics for being used for a refrigerant appliance door seal and in particular that the compositions are advantageously effective in preventing transformation and discoloration of the seal by preventing the propagation of molds and bacteria related to the

plasticizer migration.

  In the same way that the present invention can be produced in different forms without departing from the spirit or from its essential characteristics, one must

  also understand that the achievements described above

  above are not limited by any detail of the description

  previous, except to be specimens differently, but one must rather interpret them in a broad way while respecting their spirit and their range such as it is defined in

  the associated claims, and therefore the

  associated claims seek to encompass all

  changes and modifications that would relate to

  claims area or would approach it by

equivalence.

Claims (4)

  1. Polyvinyl chloride composition for a door seal for a refrigerating appliance comprising from 0.01 to 1.0% by weight of at least one biocide selected from a list comprising methyl-2benzimidazole carbamate,   2- (4-triazolyl) -benzimidazole, a- [2- (4-   chlorophenyl) -ethyl] -a- (1,1-dimethylethyl) -1H-1,2,4 triazol-1-ethanol and zinc bis (2-pyridilthio-1-oxide),   based on the weight of polyvinyl chloride.   2. Composition according to claim 1, comprising 0.1 to 0.5% by weight of at least two biocides selected from a list comprising methyl-2-benzimidazole cartamate, 2- (4-triazolyl) -benzimidazole,   a- [2- (4-chlorophenyl) -ethyl] - (1,1-dimethylethyl) -lH-   1,2,4-triazol-1-ethanol and zinc bis (2-pyridilthio-1-   oxide), based on the weight of polyvinyl chloride.   3. Composition according to claim 1, further comprising 30 to 80% by weight of a plasticizer, 1 to 5% by weight of a stabilizer, 5 to 50% by weight of a filling material and 0.001 to 1% by weight of a pigment   based on the weight of polyvinyl chloride.   2s 4. A method of manufacturing a seal for a refrigerating appliance door comprising the steps of: mixing from 0.01 to 1.0% by weight of at least one biocide selected from a list containing 2-methylbenzimidazole carbamate, 2- (4-triazolyl) -benzimidazole, from a- [2   (4-chlorophenyl) ethyl] -a- (ll-dimethylethyl) -LH-ll24-   triazol-1-ethanol and zinc bis (2-pyridilthio-1-oxide), 80% by weight of a plasticizer, 1 to 5% by weight of a stabilizer, 5 to 50% by weight of a material filling and 0.001 to 1% by weight of a pigment, in a mixer at a temperature of 50 to 120 C; pour and cool the mixture to a temperature below C in a cooling mixer to obtain a composition (formulation) in powder form; and