A soft diaper structural adhesive with high stretchability and its preparation method

Abstract

The present invention relates to C09J153 / 02, and particularly relates to a soft diaper structural adhesive with high stretchability and a preparation method thereof. By weight, the preparation raw materials include: 10-20 parts of aliphatic hydrocarbon, 15-30 parts of block copolymer, 30-50 parts of DCPD resin, 5-10 parts of modified linear resin, and ≤1 part of antioxidant. The diaper structural adhesive provided by the present invention has the advantages of high peel strength and tensile strength, moderate softening point and melt viscosity, and good coating performance.

Description

Technical Field

[0001] The present invention relates to C09J153 / 02, and particularly to a soft diaper structural adhesive with high stretchability and a preparation method thereof. Background Art

[0002] Structural adhesives have excellent adhesion and are widely used in fields such as packaging, sanitary products, and surface protective films. The quality of structural adhesives plays a crucial role in the quality of sanitary products. High-quality structural adhesives can effectively avoid phenomena such as liquid leakage in sanitary materials products such as diapers.

[0003] Patent CN202111089635.X, a diaper-specific mosquito-repellent structural adhesive and its preparation method, the structural adhesive prepared by the mutual cooperation of raw materials such as thermoplastic elastomer, paraffin wax, and naphthenic oil has the advantages of mosquito-repellent and insecticidal properties, long-lasting adhesion, and fast penetration speed.

[0004] Patent CN202111072012.1, a diaper-specific odor-removing structural adhesive and its preparation method, through the cooperation of raw materials such as naphthenic oil, pentaerythritol ester of rosin, and petroleum resin, has the advantages of good open time, high peel strength, and viscosity at low temperature.

[0005] However, the structural adhesives for diapers prepared in the prior art have poor tensile properties. During the use of diapers, due to continuous movement, the structural adhesives are stretched and broken, resulting in liquid leakage in diapers. Summary of the Invention

[0006] To solve the above technical problems, a first aspect of the present invention provides a soft diaper structural adhesive with high stretchability. By weight, the preparation raw materials include: 10-20 parts of aliphatic hydrocarbon, 15-30 parts of block copolymer, 30-50 parts of DCPD resin, 5-10 parts of modified linear resin, and ≤1 part of antioxidant.

[0007] Preferably, the aliphatic hydrocarbon includes straight-chain aliphatic hydrocarbon, branched-chain aliphatic hydrocarbon, and alicyclic hydrocarbon.

[0008] Preferably, the aliphatic hydrocarbon includes branched-chain aliphatic hydrocarbon and alicyclic hydrocarbon. The mass ratio of the branched-chain aliphatic hydrocarbon to the alicyclic hydrocarbon is (0.8-1.5):(3-5).

[0009] Preferably, the viscosity of the branched-chain aliphatic hydrocarbon at 40 °C is 25-32 mm 2 / s.

[0010] Preferably, the branched-chain aliphatic hydrocarbon is a mixture of normal and isoparaffins with C16-C31.

[0011] More preferably, the mixture of normal and isoparaffins with C16-C31 is white oil.

[0012] Preferably, the alicyclic hydrocarbon has a viscosity of 115 - 125 mm 2 / s at 40 °C.

[0013] Preferably, the alicyclic hydrocarbon is a naphthene.

[0014] Preferably, the styrene content in the block copolymer is 25 - 45 wt%.

[0015] Preferably, the block copolymer includes at least one of polystyrene - polyethylene glycol, poly(tert - butyl acrylate)-b-polystyrene, polystyrene - polybutadiene - polystyrene, polystyrene - polyisoprene - polystyrene, polystyrene - polyethylene - polybutene - polystyrene, and polystyrene - polyethylene - polybutene - polystyrene.

[0016] More preferably, the block copolymer includes polystyrene - polybutadiene - polystyrene and polystyrene - polyisoprene - polystyrene. The mass ratio of polystyrene - polybutadiene - polystyrene to polystyrene - polyisoprene - polystyrene is (5 - 10):(10 - 20).

[0017] Preferably, the styrene / isoprene block ratio in the polystyrene - polyisoprene - polystyrene is 30 / 70.

[0018] Preferably, the diblock content in the polystyrene - polyisoprene - polystyrene is 15 - 20 wt%.

[0019] Preferably, the styrene / butadiene block ratio in the polystyrene - polybutadiene - polystyrene is 43 / 57.

[0020] Preferably, the softening point of the DCPD resin is 110 - 120 °C.

[0021] Preferably, the DCPD resin includes DCPD petroleum resin and / or hydrogenated DCPD petroleum resin.

[0022] More preferably, the DCPD resin is hydrogenated DCPD petroleum resin.

[0023] Preferably, the modified linear resin is a silicon - modified linear resin.

[0024] Preferably, the raw materials for preparing the silicon - modified terpene resin include organosilicon monomers and linear resins. The mass ratio of the organosilicon monomer to the terpene resin is 1:(1 - 2).

[0025] Preferably, the organosilicon monomer includes at least one of silane, trimethylchlorosilane, propyltrimethoxysilane, n-butyldimethylchlorosilane, isooctyltriethoxysilane, vinyltriethoxysilane, octadecyltriethoxysilane.

[0026] More preferably, the organosilicon monomer is n-butyldimethylchlorosilane.

[0027] Preferably, the softening point of the linear resin is 100-110 °C.

[0028] More preferably, the linear resin is terpene resin.

[0029] Preferably, the preparation method of the silicon-modified linear resin includes the following steps:

[0030] 1) Mix and stir the linear resin and 30-40 parts of toluene evenly to obtain a mixed solution A; mix and stir the organosilicon monomer and 20-30 parts of toluene evenly to obtain a mixed solution B;

[0031] 2) Add 0.1 part of chloroplatinic acid to the mixed solution A, heat up to 40-45 °C, add the mixed solution B, seal and react for 1-2 h, heat up to 65-70 °C, continue to react for 4-7 h, evaporate under pressure to remove unreacted substances, then stir and dropwise add 30-35 parts of methanol, reflux for 1-2 h, and remove impurities by evaporation under pressure to obtain the silicon-modified linear resin.

[0032] Preferably, the antioxidant includes a hindered phenol antioxidant and / or a phosphite antioxidant.

[0033] More preferably, the antioxidant includes a hindered phenol antioxidant and a phosphite antioxidant. The mass ratio of the hindered phenol antioxidant to the phosphite antioxidant is (2-4):(5-7).

[0034] Preferably, the hindered phenol antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, 4,6-bis(octylthiomethyl)o-cresol, 4,6-bis(dodecylthiomethyl)o-cresol, 4,6-bis(dodecylthiomethyl)o-cresol, 4,6-bis(dodecylthiomethyl)o-cresol.

[0035] More preferably, the phosphite antioxidant includes tris(2,4-di-tert-butylphenyl) phosphite.

[0036] The second aspect of the present invention provides a method for preparing a soft diaper structural adhesive with high stretchability, comprising: mixing aliphatic hydrocarbons and block copolymers evenly and heating to melt for 8-15 minutes, adding DCPD resin, modified linear resin, and antioxidant and mixing evenly, heating to 150-160°C for reaction and then cooling to obtain the structural adhesive.

[0037] Beneficial effects:

[0038] 1) The present invention limits the specific types and contents of raw materials in the preparation process of the structural adhesive, uses aliphatic hydrocarbons, block copolymers, DCPD resins, modified linear resins and antioxidants as basic raw materials, and prepares the structural adhesive through a series of complex reactions and interactions. The structural adhesive has many excellent properties, such as a high ring and ball softening point, a bonding strength controlled within 1.5-3.5N / 5cm as tested by GB / T 2791-1995, and a moderate melt viscosity.

[0039] 2) The present invention uses a block copolymer of polystyrene-polybutadiene-polystyrene with a block ratio of 43 / 57 of styrene / butadiene to control the melt viscosity and peel strength to remain within an appropriate range, but it also leads to reduced elasticity and cold resistance. The present invention uses polystyrene-polybutadiene-polystyrene and polystyrene-polyisoprene-polystyrene for compounding, especially when the block ratio is 30 / 70, to control the softening point and melt viscosity of the system, extend the low-temperature opening time, and avoid the phenomenon of glue seepage. At the same time, the present invention further limits the diblock content in polystyrene-polyisoprene-polystyrene to 15-20wt%, to avoid leakage in diapers due to short adhesion time.

[0040] 3) The present invention can effectively improve the shear strength of the system by using terpene resin to interact with polystyrene-polybutadiene-polystyrene and polystyrene-polyisoprene-polystyrene in the system, avoid the lack of elasticity caused by polystyrene-polybutadiene-polystyrene, and give the structural adhesive higher elasticity, but it will also cause the thermal stability of the prepared structural adhesive to be weak. The present invention modifies the terpene resin by n-butyldimethylchlorosilane, performs a hydrosilylation reaction, and performs a hydrosilylation reaction with the intracyclic double bonds in the terpene resin, especially when the weight ratio is (1-2): 1, which can not only effectively improve the softening point and heat resistance stability of the structural adhesive, but also further control the curing speed of the glue coating, so that the peel strength is maintained in an appropriate range.

[0041] 4) Raw materials such as block copolymers contain a large number of double bonds and the temperature is relatively high during the preparation process, which easily causes the structural adhesive obtained to turn yellow and the adhesion effect to decrease. The present invention uses the combined action of DCPD hydrogenated petroleum resin, 4,6-bis(octylthiomethyl)o-cresol and 4,6-bis(dodecylthiomethyl)o-cresol. The specific functional groups contained in the molecular structure convert hydroperoxides into stable non-free radical products; especially when the mass ratio is (2-4):(5-7), it avoids excessive steric hindrance and reduces the antioxidant performance. The structural adhesive obtained has good aging resistance and yellowing resistance.

[0042] 5) The present invention uses a specific block copolymer as the main component of the structural adhesive, and uses naphthenic oil with a viscosity of 115-125 mm 2 / s at 40°C and white oil with a viscosity of 25-32 mm 2 / s at 40°C, 40 parts of DCPD resin, modified linear resin, antioxidant and other substances to further improve the crosslinked network structure of the structural adhesive, not only extending the low-temperature open time, but also having higher initial tack and holding tack. Detailed implementation mode

[0043] Examples

[0044] Example 1

[0045] A soft diaper structural adhesive with high stretchability, by weight, the preparation raw materials include: 15 parts of aliphatic hydrocarbon, 22 parts of block copolymer, 40 parts of DCPD resin, 8 parts of modified linear resin, and 0.5 part of antioxidant.

[0046] The aliphatic hydrocarbon includes branched-chain aliphatic hydrocarbon and alicyclic hydrocarbon. The mass ratio of the branched-chain aliphatic hydrocarbon to the alicyclic hydrocarbon is 1.2:4.

[0047] The branched-chain aliphatic hydrocarbon has a viscosity of 28.87 mm 2 / s at 40°C. The branched-chain aliphatic hydrocarbon is a mixture of normal and isomeric alkanes of C16-C31. The mixture of normal and isomeric alkanes of C16-C31 is white oil, purchased from Shandong Huanghe New Material Technology Co., Ltd., model: 32#.

[0048] The alicyclic hydrocarbon has a viscosity of 120.25 mm 2 / s at 40°C. The alicyclic hydrocarbon is naphthene. The naphthene is naphthenic oil, purchased from Shandong Taichang Petrochemical Technology Co., Ltd., model: N4010.

[0049] The block copolymer includes polystyrene-polybutadiene-polystyrene and polystyrene-polyisoprene-polystyrene. The mass ratio of polystyrene-polybutadiene-polystyrene to polystyrene-polyisoprene-polystyrene is 8:15.

[0050] The styrene / isoprene block ratio in the polystyrene-polyisoprene-polystyrene is 30 / 70. The diblock content in the polystyrene-polyisoprene-polystyrene is 17 wt%, purchased from Changhe Chemical Co., Ltd., Dongguan, model: D1165.

[0051] The styrene / butadiene block ratio in the polystyrene-polybutadiene-polystyrene is 43 / 57, purchased from Shanghai Furun Plastic Technology Co., Ltd., model: JSR TR2003.

[0052] The softening point of the DCPD resin is 110 - 120 °C, and the melt viscosity at 190 °C is ≤500 mPa·s. The DCPD resin is a DCPD hydrogenated petroleum resin, purchased from Puyang Kairuide Petroleum Resin Co., Ltd., model: BT-LH120.

[0053] The modified linear resin is a silicon-modified linear resin. The raw materials for preparing the silicon-modified terpene resin include organosilicon monomers and linear resins. The mass ratio of the organosilicon monomer to the terpene resin is 1:1.6.

[0054] The organosilicon monomer is n-butyldimethylchlorosilane.

[0055] The softening point of the linear resin is 100 - 110 °C. The linear resin is a terpene resin. The melt viscosity of the linear resin at 200 °C is ≤90 mPa·s, purchased from Puyang Kairuide Petroleum Resin Co., Ltd., model: TR110.

[0056] The preparation method of the silicon-modified linear resin includes the following steps:

[0057] 1) Mix 40 parts of the linear resin and 35 parts of toluene evenly to obtain mixture A; mix 25 parts of the organosilicon monomer and 25 parts of toluene evenly to obtain mixture B;

[0058] 2) Add 0.1 part of chloroplatinic acid to mixture A, heat up to 43 °C, add mixture B, seal and react for 1.5 h, heat up to 67 °C, continue to react for 5 h, evaporate under pressure to remove unreacted substances, then stir and dropwise add 32 parts of methanol, reflux for 1.5 h, and remove impurities by evaporation under pressure to obtain the silicon-modified linear resin.

[0059] The antioxidant includes a hindered phenol antioxidant and a phosphite antioxidant. The mass ratio of the hindered phenol antioxidant to the phosphite antioxidant is 3:6. The hindered phenol antioxidant includes pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]. The phosphite antioxidant includes tris[2.4-di-tert-butylphenyl]phosphite. The antioxidants are all purchased from Tianjin Lianlong New Materials Co., Ltd., model: antioxidant 1010, antioxidant 168.

[0060] A method for preparing a soft diaper structural adhesive with high stretchability comprises the following steps: aliphatic hydrocarbon and block copolymer are mixed evenly and heated to melt for 8-15 minutes, DCPD resin, modified linear resin and antioxidant are added and mixed evenly, the temperature is raised to 158°C for reaction and then cooled to obtain the structural adhesive.

[0061] Example 2

[0062] A soft diaper structural adhesive with high stretchability, the specific implementation method is the same as that of Example 1, except that the mass ratio of 4,6-bis(octylthiomethyl)-o-cresol to 4,6-bis(dodecylthiomethyl)-o-cresol is 4:7.

[0063] Example 3

[0064] A soft diaper structural adhesive with high stretchability, the specific implementation method is the same as Example 1, except that the preparation raw materials include: 20 parts of aliphatic hydrocarbon, 30 parts of block copolymer, 50 parts of DCPD resin, 10 parts of modified linear resin, and 1 part of antioxidant.

[0065] Comparative Example 1

[0066] A highly stretchable soft diaper structural adhesive, the specific implementation is the same as in Example 1, except that the styrene / isoprene block ratio in the polystyrene-polyisoprene-polystyrene is 15 / 85. The diblock content in the polystyrene-polyisoprene-polystyrene is 38wt%, purchased from Dongguan Changhe Chemical Co., Ltd., model: D1163.

[0067] Comparative Example 2

[0068] A soft diaper structural adhesive with high stretchability, the specific implementation method is the same as Example 1, except that the preparation raw materials include: 15 parts of aliphatic hydrocarbon, 22 parts of block copolymer, 40 parts of DCPD resin, 8 parts of linear resin, and 0.5 parts of antioxidant.

[0069] Performance Testing

[0070] 1. Conduct ring and ball softening point test according to GB / T 15332-94;

[0071] 2. The melt viscosity was tested in accordance with HG / T 3660-1999;

[0072] 3. The tensile strength and elongation at break were tested in accordance with GB / T 528-2008. The hot melt adhesive was heated and melted, then poured into a polytetrafluoroethylene plate with a groove thickness of 2 mm, and left at room temperature for more than one week. The specimens were cut into the specified shape with a punching machine and dumbbell-shaped cutter, and then the tensile strength was tested.

[0073] Table 1 Results of performance tests

[0074]

Claims

1. A soft diaper structure adhesive with high stretchability, characterized in that, The raw materials for preparation include, by weight: 10-20 parts of aliphatic hydrocarbon, 15-30 parts of block copolymer, 30-50 parts of DCPD resin, 5-10 parts of modified linear resin, and ≤1 part of antioxidant; The aliphatic hydrocarbons are cycloalkanes and branched aliphatic hydrocarbons, and the branched aliphatic hydrocarbons are a mixture of C16-C31 normal isoalkanes; The block copolymers include polystyrene-polybutadiene-polystyrene and polystyrene-polyisoprene-polystyrene; The mass ratio of the polystyrene-polybutadiene-polystyrene to the polystyrene-polyisoprene-polystyrene is (5-10): (10-20); The styrene / isoprene block ratio in the polystyrene-polyisoprene-polystyrene is 30 / 70, and the diblock content in the polystyrene-polyisoprene-polystyrene is 15-20wt%; The block ratio of styrene / butadiene in the polystyrene-polybutadiene-polystyrene is 43 / 57; The DCPD resin is a DCPD hydrogenated petroleum resin; The modified linear resin is a silicon-modified linear resin; The raw materials for preparing the silicon-modified linear resin include n-butyldimethylchlorosilane and terpene resin, and the mass ratio of n-butyldimethylchlorosilane to terpene resin is 1:(1-2); The antioxidants are 4,6-bis(octylthiomethyl)-o-cresol and 4,6-bis(dodecylthiomethyl)-o-cresol; the mass ratio of 4,6-bis(octylthiomethyl)-o-cresol and 4,6-bis(dodecylthiomethyl)-o-cresol is (2-4):(5-7).

2. The stretchable and soft structural adhesive for disposable diapers according to claim 1, wherein The softening point of the DCPD resin is 110-120°C.

3. A preparation method of a soft diaper structural adhesive with high stretchability according to any one of claims 1-2, characterized in that, The method comprises the following steps: mixing aliphatic hydrocarbon and block copolymer uniformly and heating to melt for 8-15 minutes, adding DCPD resin, modified linear resin and antioxidant and mixing uniformly, heating to 150-160°C for reaction and then cooling to obtain structural adhesive.

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