cant pause game when character collides,cant pause when my character dies

i have this code to pause my game when my character collides but nothing happens

 using UnityEngine;
 using System.Collections;
 
 public class Collision : MonoBehaviour
 {
     void OnCollisionEnter2D(Collision2D coll)
     {
         if (coll.gameObject.tag == "rocket")
             Destroy(gameObject);
         Time.timeScale = 0f;
     }
 }