Polycarbonate composition and preparation method thereof

Abstract

The invention discloses a polycarbonate composition and a preparation method thereof, and belongs to the technical field of high polymer materials, the polycarbonate composition adopts a compound of PC and PETG as a matrix resin system, controls the monomer proportion of PETG, and introduces a triazine light stabilizer and a composite free radical stabilizer as functional components, so that good UVC irradiation resistance can be realized, and the service life of the polycarbonate composition is prolonged. Meanwhile, enough light transmittance is achieved, and the basic processing / application ductility index when the film is applied to medical products can be met.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a polycarbonate composition and a preparation method thereof. Background Art

[0002] In the medical industry, UVC radiation disinfection is more efficient and environmentally friendly than traditional high-temperature disinfection or alcohol disinfection. It mainly relies on ultraviolet rays with a wavelength of 200-275nm, especially 250-270nm, to destroy the DNA or RNA structure of microorganisms to achieve the disinfection function. However, the current UVC radiation disinfection objects are very limited, because compared with visible light, UVC has a higher degree of photoaging, especially some degradable organic substances used in the medical field, such as polycarbonate, which have a high degree of radiation degradation under the action of UVC, and there will be obvious color difference in appearance. For this reason, people try to use various light stabilizers or degradation-resistant additives to compound to improve the appearance stability of products under UVC irradiation. However, these additives will have a greater impact on other properties of the product. For example, in the field of medical supplies, in order to facilitate use, the product is often required to have a high light transmittance, and it also needs to have sufficient processing / application ductility to adapt to various scenarios. However, the addition of various additives may cause the product's light transmittance to decrease or the ductility to deteriorate, and it cannot meet the basic application technical indicators. Summary of the invention

[0003] Based on the defects of the prior art, the purpose of the present invention is to provide a PC / PETG composition, which uses PC and PETG (polyethylene terephthalate-1,4-cyclohexane dimethanol) as a matrix resin system, controls the monomer ratio of PETG, and introduces triazine light stabilizers and composite free radical stabilizers as functional components. It can not only achieve good UVC radiation resistance, but also has sufficient light transmittance, which can meet the basic processing / application ductility indicators when used in medical products.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A PC / PETG composition comprises the following components in parts by weight:

[0006] 50-80 parts of PC resin, 20-40 parts of PETG, 0.1-3 parts of light stabilizer, 0.1-3 parts of free radical stabilizer;

[0007] The molar content of the unit derived from 1,4-cyclohexanedimethanol in the PETG is 16 to 44%;

[0008] The light stabilizer is a triazine light stabilizer;

[0009] The free radical stabilizer includes phosphazene and a compound containing a benzofuranone structure.

[0010] Preferably, the compound containing a benzofuranone structure includes at least one of benzofuranone and a benzofuranone derivative.

[0011] More preferably, the benzofuranone derivative includes at least one of 3-aryl-benzofuranone, 7-tert-butyl-5-methyl-3-(3,4-dimethyl)3-hydrogen-benzofuran-2-one, and 7-tert-butyl-5-methyl-3-(2,5-dimethyl)3-hydrogen-benzofuran-2-one.

[0012] PETG is a functional polyester with high transparency and strong resistance to whitening, but the strength and heat resistance of the substance itself are relatively poor, and it is easy to generate certain free radicals during use. At the same time, the compatibility with conventional biodegradable polyesters such as polycarbonate is not ideal, and certain ester exchange reactions will occur. For this reason, in the technical solution of the present invention, PC is compounded with PETG as the base resin, and the molar content of the 1,4-cyclohexanedimethanol monomer derivative unit in PETG is specifically regulated, so that it can effectively improve the compatibility and stability with PC resin while taking into account the balance of toughness and transmittance; for the appearance problems of PC resin and PETG under UVC irradiation, the product of the present invention is achieved by introducing specific triazine light stabilizers and free radical stabilizers into the base resin: the former It has a light absorption intensity of more than 18% at 254nm, which can help the base resin achieve high light resistance, especially UVC radiation effect, and improve the product's UVC radiation resistance. The latter includes phosphazene and benzofuranone and / or its derivatives. When releasing heat, phosphazene can release groups that capture hydrogen radicals and oxygen radicals generated by irradiation of the base resin, while benzofuranone and / or its derivatives have the function of capturing carbon radicals. The introduction of the two can regulate the ester exchange reaction between PC resin and PETG resin, and can also synergistically compound triazine light stabilizers based on the free radical capture effect to ensure that the product will not have color difference problems due to free radical effects after irradiation; in addition, the use of these two stabilizer additives will not cause the product's light transmittance and processing / toughness ductility to weaken, ensuring that the product's application indicators meet the standards.

[0013] Preferably, in the PC / PETG composition, the total mass content of PC resin and PETG is ≥90%, more preferably 95%.

[0014] The PC / PETG composition product of the present invention can achieve the expected technical effect by introducing a relatively small amount of functional additives. The controllability and operability of the PC / PETG composition product when applied to subsequent processing by those skilled in the art are better. Meanwhile, the PC / PETG composition of the present invention is not limited to the types and contents of the above-mentioned functional additive components. Without affecting the technical effect of the product, those skilled in the art may also introduce other common PC or PETG products to add additives according to actual needs.

[0015] Preferably, in the PC / PETG composition, the weight proportion of PC resin is 50 parts, 55 parts, 58 parts, 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 75 parts, 80 parts or any two of the range values, more preferably 60-70 parts; the weight proportion of PETG is 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts or any two of the range values, more preferably 30-38 parts; the weight proportion of light stabilizer is 100 parts, 150 parts, 200 parts, 250 parts, 280 parts, 300 parts, 320 parts, 350 parts, 38 ... The number of parts is 0.1 part, 0.2 part, 0.5 part, 0.8 part, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.5 parts, 3 parts or any two of the range values, more preferably 0.2-1 part; the weight number of the free radical stabilizer is 0.1 part, 0.2 part, 0.5 part, 0.8 part, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts or any two of the range values, more preferably 1-2 parts.

[0016] Preferably, the PC resin has a melt flow rate of 0.1 to 30 g / 10 min at 260° C. and a load of 2.16 kg according to ISO 1133-2-2011.

[0017] Further preferably, the PC resin has a melt flow rate of 1 to 25 g / 10 min at 260° C. and a load of 2.16 kg according to ISO 1133-2-2011.

[0018] More preferably, the PC resin is bisphenol A type PC resin.

[0019] Preferably, the phosphazene is a phosphazene compound;

[0020] More preferably, it comprises at least one of hexaphenoxy cyclotriphosphazene (CAS: 1184-10-7), hexa(4-formylphenoxy)cyclotriphosphazene, and hexachlorocyclotriphosphazene derivatives.

[0021] Preferably, the triazine light stabilizer includes at least one of triazine structures having a substituent functional group such as hydroxyphenyl triazine, methylphenyl triazine, ethyloxy triazine, etc.

[0022] Specifically, the triazine light stabilizer includes at least one of 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-hexyloxy-phenol and / or its derivatives, 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl)-5-octyloxyphenol and / or its derivatives.

[0023] Preferably, the molar content of the unit derived from 1,4-cyclohexanedimethanol in the PETG is 16%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 44% or any two of the range values;

[0024] More preferably, the molar content of the unit derived from 1,4-cyclohexanedimethanol in the PETG is 22 to 40%.

[0025] Changes in the molar content of units derived from 1,4-cyclohexanedimethanol in PETG will affect the initial transparency, strength, processing stability and UVC radiation stability of the product, thereby affecting the processing / toughness ductility, light transmittance and UVC radiation resistance of the product. When the content is preferably within the above range, the product can achieve better comprehensive performance.

[0026] It should be noted that the PETG described in the present invention can be a brand of existing commercially available products, and the property can be regulated by purchasing brand products with different molar contents of 1,4-cyclohexanedimethanol monomer derivative units. It can also be a homemade product, and the property can be regulated by conventional homemade method process regulation. Those skilled in the art can make a choice based on actual needs without any specific restrictions.

[0027] More preferably, the PETG can be prepared by self-production through monomer esterification-polycondensation reaction. Specifically, the temperature of the monomer esterification-polycondensation reaction is 225-235° C., and the monomers include terephthalic acid (PTA), ethylene glycol (EG) and 1,4-cyclohexanedimethanol (CHDM).

[0028] More preferably, the PETG can be prepared by the following method: the monomers are mixed under a nitrogen atmosphere and a titanate catalyst is added to carry out an esterification reaction at 225-235° C. and 2.8-3.2 MPa, and after the esterification water output reaches 90% or more of the theoretical value, a titanium catalyst is added to carry out a condensation reaction to obtain the PETG.

[0029] More preferably, in the monomers, the added mass ratio of terephthalic acid, ethylene glycol and 1,4-cyclohexanedimethanol is (3-4): (2.5-4): (1.5-3.5).

[0030] In the homemade method, those skilled in the art can adjust the actual added mass ratio of the monomers to control the molar content of the units derived from 1,4-cyclohexanedimethanol in the final PETG.

[0031] As mentioned above, those skilled in the art can also purchase commercially available products that meet the same conditions and use them directly, such as GN120, JN100, 5511, etc. produced by Eastman, SK Chemicals, China Resources, etc.

[0032] The molar content of the unit derived from 1,4-cyclohexanedimethanol in the PETG can be determined by infrared spectroscopy: a sample of fixed thickness is tested using a Fourier transform infrared spectrometer to obtain a characteristic absorption peak of the infrared spectrum, and the molar content of the unit derived from 1,4-cyclohexanedimethanol can be calculated by comparing the ratio of the absorbance intensity of 1,4-cyclohexanedimethanol.

[0033] Preferably, in the free radical stabilizer, the mass ratio of phosphazene to the compound containing a benzofuranone structure is (1-5):1.

[0034] More preferably, the mass ratio of the phosphazene to the compound containing a benzofuranone structure is (2-3):1.

[0035] The above two free radical stabilizers can ensure the UVC radiation resistance of the product by different ways of capturing free radicals, and based on the different compounding ratios, the acidity levels when introduced are also different, and the regulation and stability of the ester exchange reaction of PC resin and PETG are also different. When the ratio of the two is preferably within the above range, the base resin of the obtained product is more stable, and the color difference of the appearance after UVC irradiation is smaller.

[0036] Preferably, the PC / PETG composition further comprises 0.1 to 5 parts of a functional aid or a processing aid;

[0037] Further preferably, the functional additives include but are not limited to at least one of an anti-dripping agent, an antistatic agent, and an antibacterial agent, and the processing aids include at least one of a chain extender, a lubricant, and a release agent. The technicians in this field can add various functional additives or processing aids according to actual needs without affecting the expected performance of the product of the present invention. For example, in order to make the product have antistatic properties during application, the technicians in this field can add an antistatic agent to the product; in order to make the product have a better demolding effect during processing, the technicians in this field can add a small amount of lubricant or release agent to the product for lubrication.

[0038] Another object of the present invention is to provide a method for preparing the PC / PETG composition, comprising the following steps:

[0039] The components are added into a screw extruder for melt extrusion and granulation to obtain the PC / PETG composition.

[0040] Preferably, the temperature zones of the screw extruder are set to 270-290°C in zone 1, 270-290°C in zone 2, 280-260°C in zone 3, 280-260°C in zone 4, 280-260°C in zone 5, 270-260°C in zone 6, 270-260°C in zone 7, 265-250°C in zone 8, 260-240°C in zone 9, and 260-240°C in zone 10, the screw speed is 300-500rpm, and the screw aspect ratio is (45-50):1.

[0041] The preparation method of the PC / PETG composition of the present invention is simple, has low requirements on equipment, and can realize industrial-scale production.

[0042] Another object of the present invention is to provide application of the PC / PETG composition in the preparation of medical supplies.

[0043] More preferably, the medical supplies include medical device housings, wearable medical devices, injection systems, and surgical peripheral parts.

[0044] Another object of the present invention is to provide a medical product comprising the PC / PETG composition of the present invention.

[0045] The PC / PETG composition of the present invention, based on the combination of PC resin and PETG, and the auxiliary effects of specific free radical stabilizers and light stabilizers, can not only achieve good UVC radiation resistance, but also achieve excellent processing / toughness ductility and light transmittance (up to more than 85%), and is very suitable for medical products with high requirements for these properties.

[0046] The beneficial effect of the present invention is that the present invention provides a PC / PETG composition, which uses a compound of PC and PETG as a matrix resin system, controls the monomer ratio of PETG, and introduces a triazine light stabilizer and a composite free radical stabilizer as functional components, which can not only achieve good UVC radiation resistance, but also have sufficient light transmittance, and can meet basic processing / application ductility indicators when used in medical products. DETAILED DESCRIPTION

[0047] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments and comparative examples, the purpose of which is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative work premise belong to the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention, unless otherwise specified, are all commonly used common reagents and instruments.

[0048] Examples 1 to 12

[0049] The embodiments of the PC / PETG composition and the preparation method thereof of the present invention, the components of the PC / PETG composition are shown in Table 1.

[0050] The preparation method of the PC / PETG composition comprises the following steps:

[0051] The components are mixed uniformly, and then melt-extruded and granulated in a twin-screw extruder to obtain the PC / PETG composition.

[0052] When the components are melt-extruded, the temperature zones of the screw extruder are set to 280°C in zone 1, 280°C in zone 2, 270°C in zone 3, 270°C in zone 4, 270°C in zone 5, 265°C in zone 6, 265°C in zone 7, 260°C in zone 8, 250°C in zone 9, and 250°C in zone 10, the screw speed is 500rpm, and the screw aspect ratio is 48:1.

[0053] Comparative Examples 1 to 10

[0054] The difference between the comparative examples and the embodiments is only in the types and proportions of components, as shown in Table 2.

[0055] Among the components described in each embodiment and comparative example,

[0056] The PC resin 1 is PC7022PJ produced by Samyang Chemical, and the melt flow rate at 300°C and 1.2kg load is 21.5g / 10min;

[0057] The PC resin 2 is PC7030PJ produced by Samyang Chemical, and the melt flow rate at 300°C and 1.2kg load is 2.8g / 10min;

[0058] The PETG1 is a homemade product, and the molar content of the unit derived from 1,4-cyclohexanedimethanol is 23.8%. The preparation method is: the monomers are mixed under a nitrogen atmosphere and a titanate catalyst is added to carry out an esterification reaction at 230°C and 3MPa. After the esterification water output reaches 90% of the theoretical value, a titanium catalyst is added to carry out a condensation reaction to obtain the PETG; the monomers are terephthalic acid, ethylene glycol and 1,4-cyclohexanedimethanol.

[0059] The PETG2 is a homemade product, and the only difference from PETG1 is that the ratio of monomer addition materials during preparation is different, so that the mass content of units derived from 1,4-cyclohexanedimethanol in the product is 38.5%.

[0060] The PETG3 is a homemade product, and the only difference from PETG1 is that the ratio of monomer addition materials during preparation is different, so that the mass content of units derived from 1,4-cyclohexanedimethanol in the product is 19.8%.

[0061] The PETG4 is a self-made product, and the only difference from PETG1 is that the ratio of monomer addition materials during preparation is different, so that the mass content of units derived from 1,4-cyclohexanedimethanol in the product is 43.3%.

[0062] The PETG5 is a homemade product, and the only difference from PETG1 is that the ratio of monomer addition materials during preparation is different, so that the mass content of units derived from 1,4-cyclohexanedimethanol in the product is 12.7%.

[0063] The PETG6 is a homemade product, and the only difference from PETG1 is that the ratio of monomer addition materials during preparation is different, so that the mass content of units derived from 1,4-cyclohexanedimethanol in the product is 45.6%.

[0064] The light stabilizer 1 is UV1577 produced by Lianlong, 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-hexyloxy-phenol, a triazine light stabilizer;

[0065] The light stabilizer 2 is 5577 produced by Qiti, a 2 (4,6-diphenyl-1,3,5-triazine-2-yl) -5-hexyloxyphenol derivative, a triazine light stabilizer;

[0066] The light stabilizer 3 is 1164 produced by Lianlong, 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl)-5-octyloxyphenol, a triazine light stabilizer;

[0067] The light stabilizer 4 is UV360 produced by Lianlong, a benzotriazole light stabilizer.

[0068] The free radical stabilizer 1 is hexaphenoxy cyclotriphosphazene (CAS: 1184-10-7) produced by MacLean;

[0069] The free radical stabilizer 2 is TCI to produce hexa(4-formylphenoxy)cyclotriphosphazene HAPCP;

[0070] The free radical stabilizer 3 is produced by BASF 168, phosphites;

[0071] The free radical stabilizer 4 is produced by Lianlong 412S, thioester;

[0072] The free radical stabilizer 5 is Macklin produced benzofuranone (CAS: 553-86-6);

[0073] The free radical stabilizer 6 is HP-136 produced by BASF, a benzofuranone derivative, 3-aryl-benzofuranone;

[0074] The free radical stabilizer 7 is GS produced by Lianlong, bisphenol monoacrylate;

[0075] The free radical stabilizer 8 is Tinuvin 5050 produced by BASF, which replaces the hindered amine;

[0076] Unless otherwise specified, the components and raw materials used in the embodiments and comparative examples of the present invention are all commercially available raw materials, and the components and raw materials used in each parallel experiment are all of the same kind.

[0077] Table 1

[0078]

[0079]

[0080] Table 2

[0081]

[0082] In order to verify the performance of the PC / PETG composition of the present invention, the products prepared in each embodiment and comparative example were subjected to the following performance tests, and the specific steps are as follows:

[0083] (1) UVC irradiation resistance test: The L / a / b values ​​of each product test sample with a size of 125*13*2 mm were tested using a colorimeter. The number of test sites was 3 and the average value was taken. Subsequently, the parallel samples were irradiated with 253.7 nm (50 W) UVC for 50 h in an environment of 50% relative humidity and 25°C. After that, each sample was subjected to the same test as above, and the color difference ΔE was calculated based on the difference in each value.

[0084] (2) Light transmittance test: The light transmittance of each product test sample with a size of 125*13*2 mm was tested using a colorimeter (natural light source). The number of test samples for each product was 5, and the average value was taken.

[0085] (3) Ductility test: According to ASTM D3768-2011 standard, the drop speed is 2.2 m / s, the thickness of the test specimen is 2.0 mm, and the ductility of the material is judged by the failure form of 10 parallel specimens. If none of the 10 specimens are damaged, it is 100% toughness; if ≤ 3 of the 10 specimens are damaged, it is 65% toughness; if > 3 and ≤ 7 of the 10 specimens are damaged, it is 35% toughness; if > 7 of the 10 specimens are damaged or > 1 of the 10 specimens are crushed, it is brittle.

[0086] The test results are shown in Tables 3 and 4.

[0087] Table 3

[0088]

[0089] Table 4

[0090]

[0091] It can be seen from Table 3 and Table 4 that the PC / PETG composition of the present invention has ideal UVC radiation resistance, and the transmittance and ductility are also high. Specifically, the color difference ΔE of the product can still be maintained at 2.5-3.5 after long-term UVC irradiation, and the transmittance of the product can reach more than 85%. The ductility test of each product can reach 100% toughness level. This is mainly due to the introduction of PETG compounding into PC resin, and the specific regulation of the unit molar content of 1,4-cyclohexanedimethanol monomer in PETG, so that it can effectively improve the compatibility and stability with PC resin while taking into account the balance of toughness and transmittance. For PC resin and PETG under UVC irradiation, The current appearance problem is further solved by introducing specific triazine light stabilizers and free radical stabilizers into the base resin, among which the latter includes phosphazene and benzofuranone and / or its derivatives. Phosphazene can release groups that capture hydrogen free radicals and oxygen free radicals generated by irradiation of the base resin when releasing heat, while benzofuranone and / or its derivatives have the function of capturing carbon free radicals. The introduction of the two can regulate the ester exchange reaction between PC resin and PETG resin, and can also synergistically compound triazine light stabilizers to ensure that the product will not have color difference problems due to free radical effects after irradiation based on the free radical capture effect; in addition, the use of these two free radical stabilizer additives will not weaken the product's light transmittance and processing / toughness ductility, ensuring that the product's application indicators meet the standards. If only one of them is used as a free radical stabilizer, or one of them is replaced by another conventional auxiliary ingredient, as shown in Comparative Examples 1 to 7, not only the radiation resistance cannot be guaranteed, but it may even affect the transmittance and ductility of the product. The transmittance of the products in Comparative Examples 2 to 6 is less than 85%, and the ductility test of the products in Comparative Examples 5 and 6 does not meet the standard.

[0092] At the same time, in order to ensure the radiation resistance of the product, the triazine light stabilizer cannot be replaced arbitrarily, otherwise, as shown in Comparative Example 8, the radiation resistance and light transmittance of the product are not ideal.

[0093] According to the products of Examples 1 and 4 to 6 and Comparative Examples 9 to 10, it can be seen that the change in the molar content of the unit derived from 1,4-cyclohexanedimethanol in PETG will affect the initial transparency, strength, processing stability and UVC irradiation stability of the product, thereby affecting the processing / toughness ductility, light transmittance and UVC irradiation resistance of the product. Whether it is too high or too low, the product performance will not meet the standard. When the unit molar content is further preferably 22 to 40%, the comprehensive performance of the product is better. Of course, these example products are better than the products of Comparative Examples 9 and 10 with too high or too low content.

[0094] It can be seen from Example 1 and Examples 7 to 9 that when the total amount of the free radical stabilizer is constant, when the mass ratio of phosphazene to benzofuranone is (2 to 3):1, the comprehensive performance of the product is better.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A PC / PETG composition, characterized in that The composition comprises the following components in parts by weight: 50-80 parts of PC resin, 20-40 parts of PETG, 0.1-3 parts of light stabilizer, 0.1-3 parts of free radical stabilizer; The molar content of the unit derived from 1,4-cyclohexanedimethanol in the PETG is 16 to 44%; The light stabilizer is a triazine light stabilizer; The free radical stabilizer includes phosphazene and a compound containing a benzofuranone structure.

2. The PC / PETG composition according to claim 1, wherein The PC resin has a melt flow rate of 0.1 to 30 g / 10 min at 260° C. and a load of 2.16 kg according to ISO 1133-2-2011.

3. The PC / PETG composition according to claim 1, wherein The triazine light stabilizer includes at least one of hydroxyphenyl triazine, methylphenyl triazine and ethyloxy triazine.

4. The PC / PETG composition according to claim 1, wherein The molar content of the unit derived from 1,4-cyclohexanedimethanol in the PETG is 22 to 40%.

5. The PC / PETG composition according to claim 1, wherein In the free radical stabilizer, the mass ratio of phosphazene to the compound containing a benzofuranone structure is (1-5):

1.

6. The PC / PETG composition according to claim 5, wherein: The mass ratio of the phosphazene to the compound containing a benzofuranone structure is (2-3):

1.

7. The method for preparing the PC / PETG composition according to any one of claims 1 to 6, characterized in that: The following steps are involved: The components are added into a screw extruder for melt extrusion and granulation to obtain the PC / PETG composition.

8. Use of the PC / PETG composition according to any one of claims 1 to 6 in the preparation of medical supplies.

9. A medical product, characterized in that: The invention comprises the PC / PETG composition according to any one of claims 1 to 6.

10. The medical product according to claim 9, characterized in that: The medical supplies include medical device housings, wearable medical devices, injection systems, and surgical peripheral parts.

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